Bench-Scale Filtration Testing in Support of the Pretreatment Engineering Platform (PEP)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Billing, Justin M.; Daniel, Richard C.; Kurath, Dean E.

Pacific Northwest National Laboratory (PNNL) has been tasked by Bechtel National Inc. (BNI) on the River Protection Project-Hanford Tank Waste Treatment and Immobilization Plant (RPP-WTP) project to perform research and development activities to resolve technical issues identified for the Pretreatment Facility (PTF). The Pretreatment Engineering Platform (PEP) was designed, constructed and operated as part of a plan to respond to issue M12, “Undemonstrated Leaching Processes.” The PEP is a 1/4.5-scale test platform designed to simulate the WTP pretreatment caustic leaching, oxidative leaching, ultrafiltration solids concentration, and slurry washing processes. The PEP testing program specifies that bench-scale testing is to bemore » performed in support of specific operations, including filtration, caustic leaching, and oxidative leaching.« less

The enhancing of Au-Ag-Te content in tellurium-bearing ore mineral by bio-oxidation-leaching

NASA Astrophysics Data System (ADS)

Kim, PyeongMan; Kim, HyunSoo; Myung, EunJi; Kim, YoonJung; Lee, YongBum; Park*, CheonYoung

2015-04-01

The purpose of this study is to enhance the content of valuable metals such as Au-Ag-Te in tellurium-bearing minerals by bio-oxidation-leaching. It was confirmed that pyrite, chalcopyrite, sphalerite and galena were produced together with tellurium-bearing minerals including hessite, sylvanite and tellurobismuthite from ore minerals and concentrates through microscopic observation and SEM/EDS analysis. In a bio-oxidation-leaching experiment, with regard to Au, Ag, Te, Cu and Fe, the changes in the amount of leaching and the content of leaching residues were compared and analyzed with each other depending on the adaptation of an indigenous microbe identified as Acidithiobacillus ferrooxidans. As a result of the experiment, the Au-Ag-Te content in tellurium-bearing ore mineral was enhanced in the order of physical oxidation leaching, physical/non-adaptive bio-oxidation-leaching and physical/adaptive biological leaching. It suggests that the bio-oxidation-leaching using microbes adapted in tellurium-bearing ore mineral can be used as a pre-treatment and a main process in a recovery process of valuable metals. "This research was supported by Basic Science Research Program through the National Research Foundation of Korea(NRF) funded by the Ministry of Education(NRF-2013R1A1A2004898)"

The Value of Foreign Language in Business.

ERIC Educational Resources Information Center

Stebinger, Arnold

The University of South Carolina's Master's Program in International Business began in June 1974, with 43 students studying German and Spanish. The program began with a 9-week intensive language learning program, followed by a nine-month unified business program, with language instruction twice a week; six weeks of area study concentrating on the…

Women in science & engineering scholarships and summer camp outreach programs : year 7.

DOT National Transportation Integrated Search

2014-08-01

Since the UTC Scholarship program began in the spring of 2005 and continues today on the S&T campus, numerous female students : have benefitted tremendously from this source of financial aid. The program began in the first few years with 15-30 awards...

A randomized controlled trial of physical activity, dietary habit, and distress management with the Leadership and Coaching for Health (LEACH) program for disease-free cancer survivors.

PubMed

Yun, Young Ho; Kim, Young Ae; Lee, Myung Kyung; Sim, Jin Ah; Nam, Byung-Ho; Kim, Sohee; Lee, Eun Sook; Noh, Dong-Young; Lim, Jae-Young; Kim, Sung; Kim, Si-Young; Cho, Chi-Heum; Jung, Kyung Hae; Chun, Mison; Lee, Soon Nam; Park, Kyong Hwa; Park, Sohee

2017-05-02

We aimed to evaluate the potential benefits of the Leadership and Coaching for Health (LEACH) program on physical activity (PA), dietary habits, and distress management in cancer survivors. We randomly assigned 248 cancer survivors with an allocation ratio of two-to-one to the LEACH program (LP) group, coached by long-term survivors, or the usual care (UC) group. At baseline, 3, 6, and 12 months, we used PA scores, the intake of vegetables and fruits (VF), and the Post Traumatic Growth Inventory (PTGI) as primary outcomes and, for secondary outcomes, the Ten Rules for Highly Effective Health Behavior adhered to and quality of life (QOL), the Hospital Anxiety and Depression Scale (HADS), and the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ-C30). For primary outcomes, the two groups did not significantly differ in PA scores or VF intake but differed marginally in PTGI. For secondary outcomes, the LP group showed a significantly greater improvement in the HADS anxiety score, the social functioning score, and the appetite loss and financial difficulties scores of the EORTC QLQ-C30 scales from baseline to 3 months. From baseline to 12 months, the LP group showed a significantly greater decrease in the EORTC QLQ-C30 fatigue score and a significantly greater increase in the number of the Ten Rules for Highly Effective Health Behavior. Our findings indicate that the LEACH program, coached by long-term survivors, can provide effective management of the QOL of cancer survivors but not of their PA or dietary habits. Clinical trial information can be found for the following: NCT01527409 (the date when the trial was registered: February 2012).

Effect of Nutrient Management Planning on Crop Yield, Nitrate Leaching and Sediment Loading in Thomas Brook Watershed

NASA Astrophysics Data System (ADS)

Amon-Armah, Frederick; Yiridoe, Emmanuel K.; Ahmad, Nafees H. M.; Hebb, Dale; Jamieson, Rob; Burton, David; Madani, Ali

2013-11-01

Government priorities on provincial Nutrient Management Planning (NMP) programs include improving the program effectiveness for environmental quality protection, and promoting more widespread adoption. Understanding the effect of NMP on both crop yield and key water-quality parameters in agricultural watersheds requires a comprehensive evaluation that takes into consideration important NMP attributes and location-specific farming conditions. This study applied the Soil and Water Assessment Tool (SWAT) to investigate the effects of crop and rotation sequence, tillage type, and nutrient N application rate on crop yield and the associated groundwater leaching and sediment loss. The SWAT model was applied to the Thomas Brook Watershed, located in the most intensively managed agricultural region of Nova Scotia, Canada. Cropping systems evaluated included seven fertilizer application rates and two tillage systems (i.e., conventional tillage and no-till). The analysis reflected cropping systems commonly managed by farmers in the Annapolis Valley region, including grain corn-based and potato-based cropping systems, and a vegetable-horticulture system. ANOVA models were developed and used to assess the effects of crop management choices on crop yield and two water-quality parameters (i.e., leaching and sediment loading). Results suggest that existing recommended N-fertilizer rate can be reduced by 10-25 %, for grain crop production, to significantly lower leaching ( P > 0.05) while optimizing the crop yield. The analysis identified the nutrient N rates in combination with specific crops and rotation systems that can be used to manage leaching while balancing impacts on crop yields within the watershed.

The Monterey Model for Micro Business Special Education

ERIC Educational Resources Information Center

Moberg, Eric M.

2009-01-01

The following program description, literature review, and theoretical bases demonstrate the andragogical soundness of the two projects and a club of the Monterey Adult Transitions Program. The Bistro Project began as a suggestion of an Associate Superintendent, who ran a similar project in the Boston area. The Greenhouse Project began as a…

Optimal synthesis and design of the number of cycles in the leaching process for surimi production.

PubMed

Reinheimer, M Agustina; Scenna, Nicolás J; Mussati, Sergio F

2016-12-01

Water consumption required during the leaching stage in the surimi manufacturing process strongly depends on the design and the number and size of stages connected in series for the soluble protein extraction target, and it is considered as the main contributor to the operating costs. Therefore, the optimal synthesis and design of the leaching stage is essential to minimize the total annual cost. In this study, a mathematical optimization model for the optimal design of the leaching operation is presented. Precisely, a detailed Mixed Integer Nonlinear Programming (MINLP) model including operating and geometric constraints was developed based on our previous optimization model (NLP model). Aspects about quality, water consumption and main operating parameters were considered. The minimization of total annual costs, which considered a trade-off between investment and operating costs, led to an optimal solution with lesser number of stages (2 instead of 3 stages) and higher volumes of the leaching tanks comparing with previous results. An analysis was performed in order to investigate how the optimal solution was influenced by the variations of the unitary cost of fresh water, waste treatment and capital investment.

Groundwater-quality monitoring program in Chester County, Pennsylvania, 1980-2008

USGS Publications Warehouse

Senior, Lisa A.; Sloto, Ronald A.

2010-01-01

The U.S. Geological Survey in cooperation with the Chester County Water Resources Authority and the Chester County Health Department began a groundwater-quality monitoring program in 1980 in Chester County, Pa., where a large percentage of the population relies on wells for drinking-water supply. This report documents the program and serves as a reference for data collected through the program from 1980 through 2008. The initial focus of the program was to collect data on groundwater quality near suspected localized sources of contamination, such as uncontrolled landfills and suspected industrial wastes, to determine if contaminants were present that might pose a health risk to those using the groundwater. Subsequently, the program was expanded to address the effects of widely distributed contaminant sources associated with agricultural and residential land uses on groundwater quality and to document naturally occurring constituents, such as radium, radon, and arsenic, that are potential hazards in drinking water. Since 2000, base-flow stream samples have been collected in addition to well-water and spring samples in a few small drainage areas to investigate the relation between groundwater quality measured in well samples and streams. The program has primarily consisted of spatial assessment with limited temporal data collected on groundwater quality. Most data were collected through the monitoring program for reconnaissance purposes to identify and locate groundwater-quality problems and generally were not intended for rigorous statistical analyses that might determine land-use or geochemical factors affecting groundwater quality in space or through time. Results of the program found several contaminants associated with various land uses and human activities in groundwater in Chester County. Volatile organic compounds (such as trichloroethylene) were measured in groundwater near suspected localized contaminant sources in concentrations that exceeded drinking-water standards. Groundwater in some agricultural areas had concentrations of nitrate and some pesticides that exceeded drinking-water standards. Elevated concentrations of chloride were measured near salt storage areas and highways. Formaldehyde was detected in groundwater near cemeteries. In residential areas with on-site wastewater disposal, effects on groundwater quality included elevated nitrate concentrations and low concentrations of volatile organic compounds and wastewater compounds, such as antibiotics and detergents. Base-flow samples indicated that groundwater discharge to streams carried contaminants such as nitrate, pesticides, wastewater compounds, and other contaminants. Radionuclides, including radium-226, radium-228, radium-224, and radon-222, and gross alpha-particle activity were measured in groundwater at levels above established and proposed drinking-water standards in some geologic units, particularly in quartzite and quartzite schists. Arsenic concentrations above drinking-water standards were measured in a few samples and were most likely to occur in groundwater in the shales and sandstones in the northern part of the county. Other potential natural hazards, such as lead from aquifer materials or leached from plumbing because of pH, were present in concentrations above drinking-water standards infrequently (less than 10 percent of samples). Limited temporal sampling suggested that chloride concentrations in groundwater increased in the county since the program began in 1980 through 2008, reflecting increasing population and urbanization in that period.

Effects of a Parenting Program Among Women Who Began Childbearing as Adolescents and Young Adults.

PubMed

Kagawa, Rose M C; Deardorff, Julianna; García-Guerra, Armando; Knauer, Heather A; Schnaas, Lourdes; Neufeld, Lynnette M; Fernald, Lia C H

2017-11-01

The purpose of the study was to examine whether access to an at-scale, group-based parenting education program ("Educación Inicial") had differential effects on parenting behaviors and child cognitive development according to mother's age at the birth of her first child, with a focus on adolescent mothers in rural Mexico. This was a secondary analysis of a cluster-randomized controlled trial (n = 728 households, n = 106 communities). We conducted intent-to-treat analyses and examined the interaction between treatment group and mother's age at first birth. The primary outcomes were parenting behaviors (Family Care Indicators) and children's cognitive development (McCarthy Scales of Children's Abilities) at ages 3-5 years. We found that children of mothers who began childbearing in adulthood (20-30 years) scored higher on tests of cognitive development when randomized to weekly parenting support than their counterparts in the comparison group. Whereas, the children of mothers who began childbearing in adolescence (≤16 years) did not have higher scores associated with the parenting program (difference in magnitude of associations: Verbal = -8.19; 95% CI = -15.50 to -.88; p = .03; Memory = -7.22; 95% CI = -14.31 to -.14; p = .05). The higher scores among the children of mothers who began childbearing in adulthood were only significant when Educación Inical was supported by Prospera, the conditional cash transfer program. Our study results suggest that the Educación Inicial parenting intervention did not adequately address the needs of women who began childbearing in adolescence. One reason may be that adolescent mothers are more socially marginalized and less able to benefit from parenting programs. Copyright © 2017 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

Long-term high-level waste technology. Composite report

NASA Astrophysics Data System (ADS)

Cornman, W. R.

1981-12-01

Research and development studies on the immobilization of high-level wastes from the chemical reprocessing of nuclear reactor fuels are summarized. The reports are grouped under the following tasks: (1) program management and support; (2) waste preparation; (3) waste fixation; and (4) final handling. Some of the highlights are: leaching properties were obtained for titanate and tailored ceramic materials being developed at ICPP to immobilize zirconia calcine; comparative leach tests, hot-cell tests, and process evaluations were conducted of waste form alternatives to borosilicate glass for the immobilization of SRP high-level wastes, experiments were run at ANL to qualify neutron activation analysis and radioactive tracers for measuring leach rates from simulated waste glasses; comparative leach test samples of SYNROC D were prepared, characterized, and tested at LLNL; encapsulation of glass marbles with lead or lead alloys was demonstrated on an engineering scale at PNL; a canister for reference Commercial HLW was designed at PNL; a study of the optimization of salt-crete was completed at SRL; a risk assessment showed that an investment for tornado dampers in the interim storage building of the DWPF is unjustified.

Recovery audits are back: tactics for tough times.

PubMed

Cascardo, Debra

2010-01-01

The Recovery Audit Contractor (RAC) Program was implemented in stages in 2009. Section 302 of the Tax Relief and Health Care Act of 2006 required full implementation no later than January 1, 2010. The first phase began in March 2009 and covered various states; the second phase began in August 2009. The Centers for Medicare & Medicaid Services is gradually implementing the RAC permanent program, and it will ultimately affect every provider in every state.

Engineer: The Professional Bulletin of Army Engineers. Volume 42, January-April 2012

DTIC Science & Technology

2012-04-01

Maintenance Discipline Program Especially important in mechanized or wheeled ve-hicle units, this program should be bread and butter for leaders. Regular...been identified at the wrong end of the map. We contracted to have a traditional breakfast of flat- bread , sweet cream, water, and tea to serve our...talk, and exchanged cell phone numbers. Refreshments were served as we began talking about their village. The best meetings began with questions

Engaged in Debate: Major Albert C. Wedemeyer and the 1941 Victory Plan in Historical Memory

DTIC Science & Technology

2017-05-25

was simply a “ base of departure” or “benchmark” for continuing military-industrial dialogue, and, in this light, Wedemeyer’s manpower estimate was...only theaters and military operations, but manpower and industrial production as well. The result was the Victory Program, which officially began in... manpower and industrial production as well. The result was the Victory Program, which officially began in the summer of 1941 with a joint Army and Navy

Summer Research Program (1992). Graduate Student Research Programs Reports. Armstrong Laboratory. Volume 7

DTIC Science & Technology

1992-12-28

vehicle rolled over a switch which caused hydraulic cylinders to actuate. These cylinders pushed the truck from the cart, and the cart decelerated. The... hydraulic cylinders on the cart began to push the vehicle. So, to determine the exact time that the 30 cylinders began to move, plots were 25 - studied...attempts because of its dependence on well understood hydraulic principles and because of the wealth of understanding about the various constituent

Health technology assessment in the Philippines.

PubMed

De Rosas-Valera, Madeleine

2009-07-01

The aim of this study was to discuss the development of health technology assessment (HTA) in the Philippines. A new national health insurance program began to be implemented in the Philippines in 1995 after passage of the Health Insurance Act. The program is known as the Philippine Health Insurance Corporation (PhilHealth). HTA was introduced to the Philippines in 1998. PhilHealth began to develop an HTA program subsequently. As a developing country struggling to provide comprehensive health care to all citizens, PhilHealth sees HTA as an essential part of assuring that only effective and cost-effective care is provided for the public sector.

Cementitious Barriers Partnership (CBP): Training and Release of CBP Toolbox Software, Version 1.0 - 13480

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brown, K.G.; Kosson, D.S.; Garrabrants, A.C.

2013-07-01

The Cementitious Barriers Partnership (CBP) Project is a multi-disciplinary, multi-institutional collaboration supported by the Office of Tank Waste Management within the Office of Environmental Management of U.S. Department of Energy (US DOE). The CBP program has developed a set of integrated tools (based on state-of-the-art models and leaching test methods) that improve understanding and predictions of the long-term hydraulic and chemical performance of cementitious barriers used in nuclear applications. Tools selected for and developed under this program are intended to evaluate and predict the behavior of cementitious barriers used in near-surface engineered waste disposal systems for periods of performance upmore » to or longer than 100 years for operating facilities and longer than 1,000 years for waste management purposes. CBP software tools were made available to selected DOE Office of Environmental Management and field site users for training and evaluation based on a set of important degradation scenarios, including sulfate ingress/attack and carbonation of cementitious materials. The tools were presented at two-day training workshops held at U.S. National Institute of Standards and Technology (NIST), Savannah River, and Hanford included LeachXS{sup TM}/ORCHESTRA, STADIUM{sup R}, and a CBP-developed GoldSim Dashboard interface. Collectively, these components form the CBP Software Toolbox. The new U.S. Environmental Protection Agency leaching test methods based on the Leaching Environmental Assessment Framework (LEAF) were also presented. The CBP Dashboard uses a custom Dynamic-link library developed by CBP to couple to the LeachXS{sup TM}/ORCHESTRA and STADIUM{sup R} codes to simulate reactive transport and degradation in cementitious materials for selected performance assessment scenarios. The first day of the workshop introduced participants to the software components via presentation materials, and the second day included hands-on tutorial exercises followed by discussions of enhancements desired by participants. Tools were revised based on feedback obtained during the workshops held from April through June 2012. The resulting improved CBP Software Toolbox, including evaluation versions of and LeachXS{sup TM}/ORCHESTRA and STADIUM{sup R} has been made available to workshop and selected other participants for further assessment. Inquiries about future workshops and requests for access to the Toolbox software can be made via the CBP web site [1]. (authors)« less

Biological Treatment of Solvent-Based Paint

DTIC Science & Technology

2011-01-01

ESTCP Environmental Security Technology Certification Program FK-WTP Fort Kamehameha Wastewater Treatment Plant FTIR Fourier Transform Infrared...established by the Fort Kamehameha Wastewater Treatment Plant (FK-WTP) for the water; toxicity characteristic leaching procedure (TCLP) requirements for

VLEACH

EPA Science Inventory

VLEACH is a one-dimensional, finite difference model for making preliminary assessments of the effects on ground water from the leaching of volatile, sorbed contaminants through the vadose zone. The program models four main processes: liquid-phase advection, solid-phase sorption,...

Leaching of Heavy Metals from Water Bottle Components into the Drinking Water of Rodents

PubMed Central

Nunamaker, Elizabeth A; Otto, Kevin J; Artwohl, James E; Fortman, Jeffrey D

2013-01-01

Providing high-quality, uncontaminated drinking water is an essential component of rodent husbandry. Acidification of drinking water is a common technique to control microbial growth but is not a benign treatment. In addition to its potential biologic effects, acidified water might interact with the water-delivery system, leading to the leaching of heavy metals into the drinking water. The goal of the current study was to evaluate the effects of water acidification and autoclaving on water-bottle assemblies. The individual components of the system (stainless-steel sipper tubes, rubber stoppers, neoprene stoppers, and polysulfone water bottles) were acid-digested and analyzed for cadmium, chromium, copper, iron, lead, magnesium, manganese, selenium, and zinc to quantify the metal composition of each material. In addition the amounts of these metals that leached into tap and acidified water with and without autoclaving were quantified after 1 wk of contact time. On a weight basis, sipper tubes contained the largest quantities of all metals except magnesium and zinc, which were greatest in the neoprene stoppers. Except for cadmium and selenium, all metals had leached into the water after 1 wk, especially under the acidified condition. The quantities of copper, lead, and zinc that leached into the drinking water were the most noteworthy, because the resulting concentrations had the potential to confound animal experiments. On the basis of these findings, we suggest that water-quality monitoring programs include heavy metal analysis at the level of water delivery to animals. PMID:23562029

Leaching of heavy metals from water bottle components into the drinking water of rodents.

PubMed

Nunamaker, Elizabeth A; Otto, Kevin J; Artwohl, James E; Fortman, Jeffrey D

2013-01-01

Providing high-quality, uncontaminated drinking water is an essential component of rodent husbandry. Acidification of drinking water is a common technique to control microbial growth but is not a benign treatment. In addition to its potential biologic effects, acidified water might interact with the water-delivery system, leading to the leaching of heavy metals into the drinking water. The goal of the current study was to evaluate the effects of water acidification and autoclaving on water-bottle assemblies. The individual components of the system (stainless-steel sipper tubes, rubber stoppers, neoprene stoppers, and polysulfone water bottles) were acid-digested and analyzed for cadmium, chromium, copper, iron, lead, magnesium, manganese, selenium, and zinc to quantify the metal composition of each material. In addition the amounts of these metals that leached into tap and acidified water with and without autoclaving were quantified after 1 wk of contact time. On a weight basis, sipper tubes contained the largest quantities of all metals except magnesium and zinc, which were greatest in the neoprene stoppers. Except for cadmium and selenium, all metals had leached into the water after 1 wk, especially under the acidified condition. The quantities of copper, lead, and zinc that leached into the drinking water were the most noteworthy, because the resulting concentrations had the potential to confound animal experiments. On the basis of these findings, we suggest that water-quality monitoring programs include heavy metal analysis at the level of water delivery to animals.

Alteration of Chemical Composition of Soil-leached Dissolved Organic Matter under Cryogenic Cycles

NASA Astrophysics Data System (ADS)

Zhang, X.; Bianchi, T. S.; Schuur, E.

2016-02-01

Arctic permafrost thawing has drawn great attention because of the large amount of organic carbon (OC) storage in Arctic soils that are susceptible to increasing global temperatures. Due to microbial activities, some of the OC pool is converted in part to greenhouse gases, like CH4 and CO2 gas, which can result in a positive feedback on global warming. In Artic soils, a portion of OC can be mobilized by precipitation, drainage, and groundwater circulation which can in some cases be transported to rivers and eventually the coastal margins. To determine some of the mechanisms associated with the mobilization of OC from soils to aquatic ecosystems, we conducted a series of laboratory soil leaching experiments. Surface soil samples collected from Healy, Alaska were eluted with artificial rain at a constant rate. Leachates were collected over time and analyzed for dissolved organic carbon (DOC) concentrations. Concentrations began from 387-705 mg/L and then dropped to asymptote states to 25-219 mg/L. High-resolution spectroscopy was used to characterize colored dissolved organic matter (CDOM) and CDOM fluorescence intensity also dropped with time. Fluorescence maximum intensity (Fmax) for peak C ranged from 0.7-4.2 RU, with Exmax/Emmax = 310/450 nm. Fmax for peak T ranged from 0.5-3.2 RU, with Exmax/Emmax = 275/325 nm. Peak C: peak T values indicated preferential leaching of humic-like components over protein-like components. After reaching asymptotic levels, samples were stored frozen and then thawed to study the cryogenic impact on OC composition. CDOM intensity and DOC concentration increased after the freeze-thaw cycle. It was likely that cryogenic processes promoted the breakdown of OC and the releases of more DOC from soils. PARAFAC of CDOM excitation and emission matrices (EEMs) will be used to analyze CDOM composition of the soil leachates.

DISTRIBUTION COEFICIENTS (KD) GENERATED FROM A CORE SAMPLE COLLECTED FROM THE SALTSTONE DISPOSAL FACILITY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Almond, P.; Kaplan, D.

Core samples originating from Vault 4, Cell E of the Saltstone Disposal Facility (SDF) were collected in September of 2008 (Hansen and Crawford 2009, Smith 2008) and sent to SRNL to measure chemical and physical properties of the material including visual uniformity, mineralogy, microstructure, density, porosity, distribution coefficients (K{sub d}), and chemical composition. Some data from these experiments have been reported (Cozzi and Duncan 2010). In this study, leaching experiments were conducted with a single core sample under conditions that are representative of saltstone performance. In separate experiments, reducing and oxidizing environments were targeted to obtain solubility and Kd valuesmore » from the measurable species identified in the solid and aqueous leachate. This study was designed to provide insight into how readily species immobilized in saltstone will leach from the saltstone under oxidizing conditions simulating the edge of a saltstone monolith and under reducing conditions, targeting conditions within the saltstone monolith. Core samples were taken from saltstone poured in December of 2007 giving a cure time of nine months in the cell and a total of thirty months before leaching experiments began in June 2010. The saltstone from Vault 4, Cell E is comprised of blast furnace slag, class F fly ash, portland cement, and Deliquification, Dissolution, and Adjustment (DDA) Batch 2 salt solution. The salt solution was previously analyzed from a sample of Tank 50 salt solution and characterized in the 4QCY07 Waste Acceptance Criteria (WAC) report (Zeigler and Bibler 2009). Subsequent to Tank 50 analysis, additional solution was added to the tank solution from the Effluent Treatment Project as well as from inleakage from Tank 50 pump bearings (Cozzi and Duncan 2010). Core samples were taken from three locations and at three depths at each location using a two-inch diameter concrete coring bit (1-1, 1-2, 1-3; 2-1, 2-2, 2-3; 3-1, 3-2, 3-3) (Hansen and Crawford 2009). Leaching experiments were conducted with a section of core sample 3-2. All cores from location 3 were drilled without using water. Core sample 3-2 was drilled from approximately six inches to a depth of approximately 13 inches. Approximately six inches of the core was removed but it broke into two pieces during removal from the bit. At the time of drilling, core material appeared olive green in color (Smith 2008). The fact that the samples were cored as olive green and were received after storage with a gray outer layer is indicative that some oxidation had occurred prior to leaching studies.« less

Water Quality

Treesearch

Terry L. Maluk; Thomas A. Abrahamsen; Richard H. Day

2000-01-01

The U.S. Geological Survey (USGS) began the National Water-Quality Assessment Program (NAWQA) in 1991 to describe the status of and long-term trends in the quality of the Nation's surface- and ground-water resources. The study of the Santee River Basin and Coastal Drainages began in 1994 and included about 60800 km2 in North Carolina and...

Lake Ontario Tributaries: 2009-2010 Field Data Report

EPA Pesticide Factsheets

In 2002, EPA began a program to regularly monitor U.S. tributaries to Lake Ontario for the critical pollutants. This report provides program results from 2009-2010, and identifies changes in the monitoring program from prior years.

Animation of Traffic through Roundabouts

DOT National Transportation Integrated Search

1998-01-14

This report describes work done on a roundabout animation program during 1997. The roundabout animation program began as an undergraduate class project and has evolved to its current state. The program is based on the principle of an autonomous agent...

Leaching and persistence of herbicides for kudzu (Pueraria montana) control on pine regeneration sites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Berisford, Yvette, C.; Bush, Parshall, B.; Taylor, John, W.

Kudzu is an exotic vine that threatens forests in the southeastern United States. It can climb, overtop, and subsequently kill new seedlings or mature trees. Herbicides are commonly used to control kudzu; however, eradication might require retreatment for 3 to 10 yr in young stands and 7 to 10 yr for mature stands. Clopyralid, picloram, triclopyr, metsulfuron, and tebuthiuron exert various degrees of control, depending on soil type, meteorological conditions, herbicide formulation, seasonal application, characteristics of the kudzu stand, and frequency and number of herbicide. Field residue data for soil or leachate are lacking for all of these herbicides whenmore » they are used in actual forest regeneration programs in the Coastal Plain. These data are needed to assess the relative potential for the herbicides to leach into groundwater or to move off-site into sensitive ecological areas of the Coastal Plain in which sandy soils predominate and the groundwater tends to be shallow. As part of an integrated pest management program to control kudzu on forest regeneration areas at the Savannah River Site near New Ellenton, SC, five herbicides were evaluated from the standpoints of herbicide leaching, kudzu control, and plant community development. Three herbicide chemical families were represented. This included pyridinecarboxylic acid herbicides (clopyralid, picloram 1 2,4-D, and triclopyr), a sulfonylurea herbicide (metsulfuron), and a substituted urea herbicide (tebuthiuron).« less

LOOP marine and estuarine monitoring program, 1978-95 : volume 2 : water chemistry.

DOT National Transportation Integrated Search

1998-01-01

The proposed construction and use of facilities in an environmentally sensitive area led to questions about various consequential environmental impacts arising from the following activities: 1) oil storage caverns were created by leaching out a salt ...

Cultural Voucher Program; Program Abstract.

ERIC Educational Resources Information Center

Museums Collaborative, Inc., New York, NY.

A description of the Museums Collaborative Voucher Program, a system through which cultural institutions conduct programs with large, heterogeneous, adult populations in New York City is provided in this paper. The program began with two goals: to broaden the audience served by New York City's cultural institutions and to provide the institutions…

Determination of the mode of occurrence of As, Cr, and Hg in three Chinese coal samples by sequential acid leaching

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, B.; Li, W.; Wang, G.

2007-07-01

Sequential acid leaching was used to leach minerals and the trace elements they contain. One-step leaching uses concentrated nitric acid as solvent, while three-step leaching uses 5M hydrochloric acid, concentrated hydrofluoric acid, and concentrated hydrochloric acid as solvents. The sequential acid leaching by three-and one-step leach was also examined. The results showed that one-step leaching could leach over 80% of arsenic from coal samples, and also could leach mercury to a certain degree. During one-step leaching, little chromium is removed, but it is available to leach by three-step leaching; and during the sequential acid leaching by three and one-step leaching,more » almost 98% ash is leached. The result of acid leaching could also give detailed information on mode of occurrence of As, Cr, and Hg, which could be classified into: silicate association, pyrite association, organic association, and carbonates and sulfates association. Over half of chromium in the three coals is associated with organic matters and the rest is associated with silicates. The mode of occurrence of arsenic and mercury is mainly associated with different mineral matters depending on the coal samples studied.« less

UIUC concrete tie and fastener field testing at TTC.

DOT National Transportation Integrated Search

2014-07-01

In July 2012, the University of Illinois at Urbana-Champaign (UIUC) began an extensive : experimental program at the Transportation : Technology Center (TTC) in Pueblo, CO. The : field experimentation program was part of a : larger research program f...

Integrated vehicle-based safety systems : first annual report

DOT National Transportation Integrated Search

2007-10-01

The IVBSS (Integrated Vehicle-Based Safety Systems) program is a four-year, two phase cooperative research program being conducted by an industry team led by the University of Michigan Transportation Research Institute (UMTRI). The program began in N...

Pepnet 2: Developing Collaborative Relationships for Effective Transition Services

ERIC Educational Resources Information Center

Kolvitz, Marcia

2016-01-01

The foundation for pepnet 2 began in the late 1960s when the U.S. Department of Education provided funding to establish four programs for the deaf at postsecondary institutions across the country. As an increasing number of deaf and hard of hearing students began enrolling in mainstreamed colleges throughout the country, the focus of federal…

An Interdistrict Transfer Program

ERIC Educational Resources Information Center

Gross, Norman

1975-01-01

This testimony, before the May 1974 public hearings of the New York City Commission on Human Rights by the Administrator, Urban-Suburban Transfer Program and Inter district Transfer Program, West Irondequoit School District, New York, reviews a program which began with 25 minority group youngsters from one racially-imbalanced Rochester school…

Darwin : The Third DOE ARM TWP ARCS Site /

DOE Office of Scientific and Technical Information (OSTI.GOV)

Clements, William E.; Jones, L. A.; Baldwin, T.

2002-01-01

The United States Department of Energy's (DOE) Atmospheric Radiation Measurement (ARM) Program began operations in its Tropical Western Pacific (TWP) locale in October 1996 when the first Atmospheric Radiation and Cloud Station (ARCS) began collecting data on Manus Island in Papua New Guinea (PNG). Two years later, in November 1998, a second ARCS began operations on the island of Nauru in the Central Pacific. Now a third ARCS has begun collecting data in Darwin, Australia. The Manus, Nauru, and Darwin sites are operated through collaborative agreements with the PNG National Weather Service, The Nauru Department of Industry and Economic Developmentmore » (IED), and the Australian Bureau of Meteorology's (BOM) Special Services Unit (SSU) respectively. All ARM TWP activities in the region are coordinated with the South Pacific Regional Environment Programme (SPREP) based in Apia, Samoa. The Darwin ARM site and its role in the ARM TWP Program are discussed.« less

Ultrasound-assisted HCl-NaCl leaching of lead-rich and antimony-rich oxidizing slag.

PubMed

Zhang, Rong Liang; Zhang, Xiao Fei; Tang, Shu Zhen; Huang, Ai Dong

2015-11-01

Lead-rich and antimony-rich oxidizing slag was subjected to regular HCl-NaCl leaching, with the experimental conditions optimized under which ultrasound was introduced. After only 15 min of ultrasound-assisted leaching, the leaching rate of Sb resembled that after 45 min of regular leaching. Ultrasonic treatment considerably elevated the leaching rates of Sb and Pb, and shortened the leaching time. With the decrease of particle size, the leaching rate of Sb and Pb increased gradually. Especially, as the particle size of the slag was greater than 0.217 mm, the ultrasonic leaching effects of Sb and Pb were significantly higher than that of regular leaching effects. The temperature exhibited great effect on ultrasonic leaching performance. As the temperature increased, the leaching rates of Sb and Pb increased step by step. In case the temperature was higher than 85°C, the increasing speed of the leaching rates for Sb and Pb tended to be slow. Increasing ultrasonic power could augment the leaching rate or accelerate the procedure till the same leaching rate. However, since ultrasound failed to energize the formation of new reaction pathways, the maximum leaching rates of Sb and Pb were determined by their phase compositions rather than by ultrasonic field. Copyright © 2015 Elsevier B.V. All rights reserved.

Influencing factors and kinetics analysis on the leaching of iron from boron carbide waste-scrap with ultrasound-assisted method.

PubMed

Li, Xin; Xing, Pengfei; Du, Xinghong; Gao, Shuaibo; Chen, Chen

2017-09-01

In this paper, the ultrasound-assisted leaching of iron from boron carbide waste-scrap was investigated and the optimization of different influencing factors had also been performed. The factors investigated were acid concentration, liquid-solid ratio, leaching temperature, ultrasonic power and frequency. The leaching of iron with conventional method at various temperatures was also performed. The results show the maximum iron leaching ratios are 87.4%, 94.5% for 80min-leaching with conventional method and 50min-leaching with ultrasound assistance, respectively. The leaching of waste-scrap with conventional method fits the chemical reaction-controlled model. The leaching with ultrasound assistance fits chemical reaction-controlled model, diffusion-controlled model for the first stage and second stage, respectively. The assistance of ultrasound can greatly improve the iron leaching ratio, accelerate the leaching rate, shorten leaching time and lower the residual iron, comparing with conventional method. The advantages of ultrasound-assisted leaching were also confirmed by the SEM-EDS analysis and elemental analysis of the raw material and leached solid samples. Copyright © 2017 Elsevier B.V. All rights reserved.

PEP Support: Laboratory Scale Leaching and Permeate Stability Tests

DOE Office of Scientific and Technical Information (OSTI.GOV)

Russell, Renee L.; Peterson, Reid A.; Rinehart, Donald E.

2010-05-21

This report documents results from a variety of activities requested by the Hanford Tank Waste Treatment and Immobilization Plant (WTP). The activities related to caustic leaching, oxidative leaching, permeate precipitation behavior of waste as well as chromium (Cr) leaching are: • Model Input Boehmite Leaching Tests • Pretreatment Engineering Platform (PEP) Support Leaching Tests • PEP Parallel Leaching Tests • Precipitation Study Results • Cr Caustic and Oxidative Leaching Tests. Leaching test activities using the PEP simulant provided input to a boehmite dissolution model and determined the effect of temperature on mass loss during caustic leaching, the reaction rate constantmore » for the boehmite dissolution, and the effect of aeration in enhancing the chromium dissolution during caustic leaching. Other tests were performed in parallel with the PEP tests to support the development of scaling factors for caustic and oxidative leaching. Another study determined if precipitate formed in the wash solution after the caustic leach in the PEP. Finally, the leaching characteristics of different chromium compounds under different conditions were examined to determine the best one to use in further testing.« less

Preliminary assessment of sources of nitrogen in groundwater at a biosolids-application area near Deer Trail

USGS Publications Warehouse

Yager, Tracy J.B.; McMahon, Peter B.

2012-01-01

Concentrations of dissolved nitrite plus nitrate increased fairly steadily in samples from four shallow groundwater monitoring wells after biosolids applications to nonirrigated farmland began in 1993. The U.S. Geological Survey began a preliminary assessment of sources of nitrogen in shallow groundwater at part of the biosolids-application area near Deer Trail, Colorado, in 2005 in cooperation with the Metro Wastewater Reclamation District. Possible nitrogen sources in the area include biosolids, animal manure, inorganic fertilizer, atmospheric deposition, and geologic materials (bedrock and soil). Biosolids from the Metro Wastewater Reclamation District plant in Denver and biosolids, cow manure, geologic materials (bedrock and soil), and groundwater from the study area were sampled to measure nitrogen content and nitrogen isotopic compositions of nitrate or total nitrogen. Biosolids also were leached, and the leachates were analyzed for nitrogen content and other concentrations. Geologic materials from the study area also were sampled to determine mineralogy. Estimates of nitrogen contributed from inorganic fertilizer and atmospheric deposition were calculated from other published reports. The nitrogen information from the study indicates that each of the sources contain sufficient nitrogen to potentially affect groundwater nitrate concentrations. Natural processes can transform the nitrogen in any of the sources to nitrate in the groundwater. Load calculations indicate that animal manure, inorganic fertilizer, or atmospheric deposition could have contributed the largest nitrogen load to the study area in the 13 years before biosolids applications began, but biosolids likely contributed the largest nitrogen load to the study area in the 13 years after biosolids applications began. Various approaches provided insights into sources of nitrate in the groundwater samples from 2005. The isotopic data indicate that, of the source materials considered, biosolids and (or) animal manure were the most likely sources of nitrate in the wells at the time of sampling (2005), and that inorganic fertilizer, atmospheric deposition, and geologic materials were not substantial sources of nitrate in the wells in 2005. The large total nitrogen content of the biosolids and animal-manure samples and biosolids leachates also indicates that the biosolids and animal manure had potential to leach nitrogen and produce large dissolved nitrate concentrations in groundwater. The available data, however, could not be used to distinguish between biosolids or manure as the dominant source of nitrate in the groundwater because the nitrogen isotopic composition of the two materials is similar. Major-ion data also could not be used to distinguish between biosolids or manure as the dominant source of nitrate in the groundwater because the major-ion composition (as well as the isotopic composition) of the two materials is similar. Without additional data, chloride/bromide mass ratios do not necessarily support or refute the hypothesis that biosolids and (or) animal manure were the primary sources of nitrate in water from the study-area wells in 2005. Concentrations of water-extractable nitrate in the soil indicate that biosolids could be an important source of nitrate in the groundwater recharge. Nitrogen inventories in the soil beneath biosolids-application areas and the nitrogen-input estimates for the study area both support the comparisons of isotopic composition, which indicate that some type of human waste (such as biosolids) and (or) animal manure was the source of nitrate in groundwater sampled from the wells in 2005. The nitrogen-load estimates considered with the nitrogen isotopic data and the soil-nitrogen inventories indicate that biosolids applications likely are a major source of nitrogen to the shallow groundwater at these monitoring wells.

Ultrasound-assisted leaching of rare earths from the weathered crust elution-deposited ore using magnesium sulfate without ammonia-nitrogen pollution.

PubMed

Yin, Shaohua; Pei, Jiannan; Jiang, Feng; Li, Shiwei; Peng, Jinhui; Zhang, Libo; Ju, Shaohua; Srinivasakannan, Chandrasekar

2018-03-01

The in situ leaching process of China's unique ion-adsorption rare earth ores has caused severe environmental damages due to the use of (NH 4 ) 2 SO 4 solution. This study reports that magnesium sulfate (MgSO 4 ) as a leaching agent would replace (NH 4 ) 2 SO 4 by ultrasonically assisted leaching to deal with the ammonia-nitrogen pollution problem and enhance leaching process. At leaching conditions of 3wt% MgSO 4 concentration, 3:1L/S ratio and 30min, the total rare earth leaching efficiency reaches 75.5%. Ultrasound-assisted leaching experiments show that the leaching efficiency of rare earths is substantially increased by introducing ultrasound, and nearly completely leached out after two stage leaching process. Thus, ultrasonic-assisted leaching process with MgSO 4 is not only effective but also environmentally friendly, and beneficial to leach rare earths at laboratory scale. Copyright © 2017 Elsevier B.V. All rights reserved.

The Heart of the Mission

ERIC Educational Resources Information Center

Forest, Angela

2008-01-01

This article discusses the Urban Health Program, a University of Illinois at Chicago program that seeks to improve the quality of medical care in communities of color. The UIC program began in 1968 to attract and train minority medical students. In 1978, the Illinois Legislature expanded the program, renaming it the Urban Health Program (UHP), in…

Forest gene conservation programs in Alberta, Canada

Treesearch

Jodie Krakowski

2017-01-01

Provincial tree improvement programs in Alberta began in 1976. Early gene conservation focused on ex situ measures such as seed and clone banking, and research trials of commercial species with tree improvement programs. The gene conservation program now encompasses representative and unique populations of all native tree species in situ. The ex situ program aims to...

The Family & Life Education Program.

ERIC Educational Resources Information Center

Brand, Mellie R.

The Family and Life Education program at Aims Community College (ACC) in Colorado began in 1967 as prenatal classes taught by volunteer instructors who were registered nurses with backgrounds in maternal-child health. Currently, the program, which is co-sponsored by ACC and North Colorado Medical Center, involves a program coordinator, three staff…

Franchisees boost growth of Hispanic PPO.

PubMed

Greene, J

1991-10-07

What began as a local marketing effort by two Chicago hospitals to reach the city's fast-growing Hispanic population has turned into a national program with franchises in San Diego and San Antonio, Texas. Formed in 1989, Hispanocare, a preferred provider organization catering to Hispanics, began attracting attention in other cities with large Hispanic populations, prompting the Chicago hospitals to begin a marketing push.

Design, development, and evaluation of truck and bus driver wellness programs

DOT National Transportation Integrated Search

2000-06-01

In May 1997, the Federal Motor Carrier Safety Administration (FMCSA) began a research project to design, develop, and evaluate a model truck and bus driver wellness program. This wellness program was developed to provide a resource for addressing tru...

Research on the effect of alkali roasting of copper dross on leaching rate of indium

NASA Astrophysics Data System (ADS)

Dafang, Liu; Fan, Xingxiang; Shi, Yifeng; Yang, Kunbin

2017-11-01

The byproduct copper dross produced during refining crude lead was characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and fluorescence spectrometer (XRF), which showed that copper dross mainly contained lead, copper, zinc, arsenic, antimony, bismuth, sulfur and a small amount of indium and silver etc. The mineralogical phase change of oxidation roasting of copper dross by adding sodium hydroxide was analyzed with the help of XRD and SEM. The effects of water leaching, ratio of sodium hydroxide, roasting time, and roasting temperature on leaching rate of indium were investigated mainly. The experimental results showed that phase of lead metal and sulfides of lead, copper and zinc disappeared after oxidation roasting of copper dross by adding sodium hydroxide, new phase of oxides of lead, copper, zinc and sodium salt of arsenic and antimony appeared. Water leaching could remove arsenic, and acid leaching residue obtained was then leached with acid. The leaching rate of indium was higher 6.98% compared with alkali roasting of copper dross-acid leaching. It showed that removing arsenic by water leaching and acid leaching could increase the leaching rate of indium and be beneficial to reducing subsequent acid consumption of extracting indium by acid leaching. The roasting temperature had a significant effect on the leaching rate of indium, and leaching rate of indium increased with the rise of roasting temperature. When roasting temperature ranged from 450°C to 600°C, leaching rate of indium increased significantly with the rise of roasting temperature. When roasting temperature rose from 450°C to 600°C, leaching rate of indium increased by 60.29%. The amount of sodium hydroxide had an significant effect on the leaching rate of indium, and the leaching of indium increased with the increase of the amount of sodium hydroxide, and the leaching rate of indium was obviously higher than that of copper dross blank roasting and acid leaching.

Comparison of Ultrasound-Assisted and Regular Leaching of Vanadium and Chromium from Roasted High Chromium Vanadium Slag

NASA Astrophysics Data System (ADS)

Wen, Jing; Jiang, Tao; Gao, Huiyang; Liu, Yajing; Zheng, Xiaole; Xue, Xiangxin

2018-02-01

Ultrasound-assisted leaching (UAL) was used for vanadium and chromium leaching from roasted material obtained by the calcification roasting of high-chromium-vanadium slag. UAL was compared with regular leaching. The effect of the leaching time and temperature, acid concentration, and liquid-solid ratio on the vanadium and chromium leaching behaviors was investigated. The UAL mechanism was determined from particle-size-distribution and microstructure analyses. UAL decreased the reaction time and leaching temperature significantly. Furthermore, 96.67% vanadium and less than 1% chromium were leached at 60°C for 60 min with 20% H2SO4 at a liquid-solid ratio of 8, which was higher than the maximum vanadium leaching rate of 90.89% obtained using regular leaching at 80°C for 120 min. Ultrasonic waves broke and dispersed the solid sample because of ultrasonic cavitation, which increased the contact area of the roasted sample and the leaching medium, the solid-liquid mass transfer, and the vanadium leaching rate.

Enhancement of gold grade through arsenic removal in the gold concentrate using sulfuric acid baking and hot water leaching

NASA Astrophysics Data System (ADS)

On, Hyun-sung; Lim, Dae-hack; Myung, Eun-ji; Kim, Hyun-soo; Park, Cheon-young

2017-04-01

In order to improve gold recovery, in general, the roasting process is carried out on gold concentrate. However in this process, Arsenic(As) is released from the gold concentrate and valuable elements such as Fe, Cu, Zn and Pb are converted into oxides. This causes air pollution through the release of As and loss of valuable elements by discarding the oxide minerals in the tailings. In order to prevent the release of As and the loss of valuable metals, an acid baking experiment was carried out on the gold concentrate with the addition of an H2SO4 solution. The baking effect, H2SO4 concentration effect and the effects of changing the baking time were examined using an electric furnace. In experimental results, soluble metal sulfates such as Rhomboclase and Mikasite were formed in the baked samples as seen through XRD analysis. In hot(70 degree Celsius) water leaching of the roast and baked samples, As the contents leached were 60 times more in the baked sample than the roast sample, and the Fe, Cu, Zn and Pb contents were 17, 10, 14, 13 times in the baked sample than in the roast sample, respectively. In the water leached solid-residues, the maximum gold grade was upgraded by 33% due to the acid baking effect. It is confirmed that acid baking with H2SO4 prevented As release into the air and the recovery of valuable metals through hot water leaching such as Fe, Cu, Zn and Pb which were formerly discarded in the tailings. Acknowledgment : This work was supported by the Energy and Resources Engineering Program Grant funded by the Ministry of Trade, Industry and Energy, Korea

Lessons Learned about Workplace Literacy from Military Job-Specific Reading Programs.

ERIC Educational Resources Information Center

Philippi, Jorie W.

For almost half a century the United States military services have incorporated formal literacy programs into job training for those enlistees who are less than fully qualified. Over the years, several successful job-specific reading programs have evolved. In 1975, the Army began the Functional Literacy (FLIT) Program, a program based on a…

Some Outcomes of an Employment-Oriented Post-Secondary Training Program for Educably Mentally Handicapped Adults.

ERIC Educational Resources Information Center

Fahy, P.; McLean, A.

The Alberta Vocational Centre (AVC) Transitional Vocational (T-V) Program, in Edmonton, began in 1982. The program currently employs six instructors to provide a postsecondary employment-oriented program for mildly mentally disabled adults. The yearlong program is offered in two sessions and has an approximate enrollment of 30 incoming students…

Doctoral Study Programs in Social Work at HBCUs: Origin and Program Development

ERIC Educational Resources Information Center

Aubrey, Hal; Jordan, Tina; Stevenson, Andre P.; Boss-Victoria, Rena; Haynes, James; Estreet, Anthony; Smith, Jahmaine; Cameron, Elijah; Williams, Quotasze

2016-01-01

Fisk University began the genesis of HBCU graduate programs in 1880. During the next fifty years, several other HBCUs established graduate programs. That group included Lincoln, Howard, and Morgan State. However, only Lincoln University established a PhD program. The primary goal of this paper is to provide a historical perspective regarding the…

Leaching Test Relationships, Laboratory-to-Field Comparisons and Recommendations for Leaching Evaluation using the Leaching Environmental Assessment Framework (LEAF)

EPA Science Inventory

This report presents examples of the relationships between the results of laboratory leaching tests, as defined by the Leaching Environmental Assessment Framework (LEAF) or analogous international test methods, and leaching of constituents from a broad range of materials under di...

Student Issues in Distance Education Programs: Do Inter-institutional Programs Offer Students More Confusion or More Opportunities?

ERIC Educational Resources Information Center

Fey, Susan; Emery, Mary; Flora, Cornelia

2008-01-01

The Community Development Master's Program is an inter-institutional, trans-disciplinary degree program that began in 2005 online at five participating universities in the North Central region. This article discusses outcomes of interviews with current and past students in the program to determine if a multi-institutional program, versus a program…

Out of Boom and Bust, but Where to now for Geoscience Departments?

NASA Astrophysics Data System (ADS)

Keane, C. M.

2005-12-01

For most of the last 50 years, the fortunes of geoscience programs at the university level have waxed and waned with the health of the natural resources industries. These industries, and petroleum in particular, have experience major boom and bust cycles, of which geoscience programs often mirrored. This relationship began to change in the early 1990's when many geosciences programs began to offer environmental concentrations. This shift only lasted about five years before job opportunities began to decline in that field as well. By the mid 1990s, for the first time, the fortunes of geoscience departments began to mirror the overall trend of the other physical sciences - and just at the wrong time. The dot-com boom put negative pressure on enrollments, but since 2001, the geosciences, like many sciences, have now begun to experience 4-6 percent enrollment growth each year. Through all of this a number of departments have largely remained strong, and continue to grow. The trends of growth through the past twenty-five years gives us some insight into what healthy departments are doing right, and what opportunities exist for future growth for all programs. Two aspects of successful programs of particular note are those that retained strong, core basic geology academic programs, and those that continue to actively produce master's students. In particular, the master's level poses a unique opportunity for departmental growth. In other science disciplines, combined science master's with MBA's are generating substantial revenue for schools and enhancing the science program's status within the university community and the potential employer pool. However, though the number of master's degrees awarded in the geosciences has remained relatively steady, the number of schools that are actually awarding degrees has shrunk substantially, with the historically strong departments producing a large proportion of master's recipients. The challenge is to now 'read the tea leaves' of what future department success will require in an era of largely replacement-level hiring in the traditional geoscience job sectors and continuing shrinking federal research support. Recent departmental successes point to what appears to be paths for strong a strong future.

Polymer concrete overlay test program : final report.

DOT National Transportation Integrated Search

1981-12-01

The results in this report were obtained during the test program which began in 1973. Physical properties of various polymer concretes are listed. They include compressive strength, splitting tensile strength, bond strength, the modulus of elasticity...

Test Program Seeks to Lower School Heating Costs.

ERIC Educational Resources Information Center

School Business Affairs, 1980

1980-01-01

As part of the second year of its Schoolhouse Energy Efficiency Demonstration (SEED) program, Tenneco, Inc. recently began a test of experimental window insulation material in three of the schools audited last year. (Author/MLF)

Challenges in Addressing Variability Of Lead in Domestic Plumbing

EPA Science Inventory

Current data indicate that lead exposure is of concern even at low concentrations. Corrosion is an important problem in drinking water because it can affect public health due to leaching of lead or other metals into the drinking water. For this reason, a corrosion control program...

The Work Experience Component of an Ontario College Baccalaureate Program

ERIC Educational Resources Information Center

Donohue, Marguerite M.; Skolnik, Michael L.

2012-01-01

Community colleges in Canada began offering baccalaureate programs in the 1990s. Presently community colleges in four of the five largest provinces of Canada are eligible to submit applications to the relevant government ministry or agency for baccalaureate programs. The authors estimate that about 135 baccalaureate programs are now being offered…

Increasing Retention and Graduation Rates through a STEM Learning Community

ERIC Educational Resources Information Center

Dagley, Melissa; Georgiopoulos, Michael; Reece, Amber; Young, Cynthia

2016-01-01

The EXCEL Program began as a National Science Foundation-sponsored STEM Talent Expansion Program in 2006 and, because of its significant impact on retention of STEM majors, has since become an institutionalized program at the University of Central Florida. The University of Central Florida EXCEL Program annually recruits approximately 200…

Program Theory and Quality Matter: Changing the Course of Extension Program Evaluation

ERIC Educational Resources Information Center

Arnold, Mary E.; Cater, Melissa

2016-01-01

As internal evaluators for the 4-H program in two states, we simultaneously yet independently began to change the way we approached our evaluation practices, turning from evaluation capacity building (ECB) efforts that prepared educators to define and measure program outcomes to strategies that engage educators in defining and measuring program…

Better Building Blocks

Treesearch

Cheryl R. Renner; Terry K. Haines; Margaret A. Reams

2010-01-01

As researchers for the National Database of State and Local Wildfire Mitigation Programs, we began cataloging programs to reduce wildfire risk on private land in 2001. Over the years, more than 250 programs in 35 states were described at www.wildfireprograms.usda.gov, and we wondered about their relative success. Was there one type of program that wildfire managers...

The School Breakfast Program

ERIC Educational Resources Information Center

US Department of Agriculture, 2009

2009-01-01

The School Breakfast Program is a federally assisted meal program operating in public and nonprofit private schools and residential child care institutions. It began as a pilot project in 1966, and was made permanent in 1975. The School Breakfast Program is administered at the Federal level by the Food and Nutrition Service. At the State level,…

How We Began - About the Guard - The National Guard

Science.gov Websites

Partnership Program Special Features Your National Guard About the Guard How We Began Air National Guard Army National Guard About Us By the Numbers Contact Us FAQ Federal Mission History Join Us Leaders Director of the ARNG Deputy Director of the ARNG Chief of Staff of the ARNG Command Chief Warrant Officer of the

Ultrasound augmented leaching of nickel sulfate in sulfuric acid and hydrogen peroxide media.

PubMed

Li, Haoyu; Li, Shiwei; Peng, Jinhui; Srinivasakannan, Chandrasekar; Zhang, Libo; Yin, Shaohua

2018-01-01

A new method of preparation high purity nickel sulfate assisted by ultrasonic was studied. The process mechanism was analyzed by Inductively Coupled Plasma (ICP), X-ray diffraction (XRD), Scanning electron microscopy (SEM), and Energy dispersive X-ray spectrometry (EDS).The reaction mechanisms of oxidizing leaching and ultrasonic leaching were explored, respectively. Results showed that ultrasonic treatment peel off the oxide film on the surface of nickel. The leachate under strongly agitated, the yield rate of nickel sulfate was accelerate. And the reaction area was increased by the cavitation effect, the liquid-solid reaction was promoted, and the activation energy was reduced. The leaching rate of nickel reached 46.29% by conventional leaching, which takes about 5h. Under the same conditions, the ultrasonic leaching rate reached 40%, only half of the conventional leaching time. Concentration of leaching agent, reaction temperature, ultrasonic power, leaching time had significant effect on the enhancement of the leaching reaction with ultrasonic radiation. The leaching rate of 60.41% under the optimum experiment conditions as follows: sulfuric acid concentration 30%, hydrogen peroxide 10%, leaching temperature 333K, ultrasonic power 200W and leaching time 4h. The kinetic study of the system was investigated, and the reaction rates of conventional leaching and ultrasonic leaching were controlled by diffusion, and the apparent activation energies were 16.2kJ/mol and 11.83kJ/mol. Copyright © 2017. Published by Elsevier B.V.

The Arizona Performance-Based Teacher Certification Program.

ERIC Educational Resources Information Center

Kelley, Michael F.

In response to public pressures and a legislative mandate, the State of Arizona began to systematically evaluate prospective teachers while concomitantly requiring a restructuring of the Arizona teacher preparation programs at the college and university level as part of a program entitled the Arizona Performance-Based Teacher Certification…

Spanish for Professionals.

ERIC Educational Resources Information Center

Casellas de Kelly, Maria del Rosario

A University of New Mexico program in Spanish for professionals began in 1981 as a Spanish and Portuguese program to provide language training for personnel in health care, business, law, and education. The program encountered early problems of uneven enrollments, funding difficulties, and some lack of interest from the campus professional schools…

New Start Program Report: September 1985--June 1989.

ERIC Educational Resources Information Center

Winchell, Anne

In 1985, Kingsborough Community College (KCC) in Brooklyn, established the New Start Program to assist students who began their post-secondary education at cooperating senior colleges, but encountered academic difficulties there. The program offers individual and group counseling to help participants overcome previous difficulties and work toward…

Statistical comparison of leaching behavior of incineration bottom ash using seawater and deionized water: Significant findings based on several leaching methods.

PubMed

Yin, Ke; Dou, Xiaomin; Ren, Fei; Chan, Wei-Ping; Chang, Victor Wei-Chung

2018-02-15

Bottom ashes generated from municipal solid waste incineration have gained increasing popularity as alternative construction materials, however, they contains elevated heavy metals posing a challenge for its free usage. Different leaching methods are developed to quantify leaching potential of incineration bottom ashes meanwhile guide its environmentally friendly application. Yet, there are diverse IBA applications while the in situ environment is always complicated, challenging its legislation. In this study, leaching tests were conveyed using batch and column leaching methods with seawater as opposed to deionized water, to unveil the metal leaching potential of IBA subjected to salty environment, which is commonly encountered when using IBA in land reclamation yet not well understood. Statistical analysis for different leaching methods suggested disparate performance between seawater and deionized water primarily ascribed to ionic strength. Impacts of leachant are metal-specific dependent on leaching methods and have a function of intrinsic characteristics of incineration bottom ashes. Leaching performances were further compared on additional perspectives, e.g. leaching approach and liquid to solid ratio, indicating sophisticated leaching potentials dominated by combined geochemistry. It is necessary to develop application-oriented leaching methods with corresponding leaching criteria to preclude discriminations between different applications, e.g., terrestrial applications vs. land reclamation. Copyright © 2017 Elsevier B.V. All rights reserved.

Air Traffic Control: Remote Radar For Grand Junction

DOT National Transportation Integrated Search

1996-11-01

In 1983, the Federal Aviation Administration (FAA) began a nationwide program : of consolidating air traffic control facilities to gain the benefits of : automation and any attendant cost savings. As part of this program, FAA : conducted several stud...

ION EXCHANGE TESTS ON LIQUOR AND PULPS PRODUCED FROM UTEX ORES. Topical Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hollis, E.T.; Pickwick, F.J. Jr.; Kazanjian, A.R.

1954-07-30

Uranium leach liquors produced from Utex ore by cold leaching, hot leaching, and pugging proved amenable to the lon exchange process, Higher resin loadings were obtained rom the cold leach liquors than from the hot leach and pug liquors. In general, the less vigorous leaching conditions produced liquors which gave the highest resin loadings. In addition, a resin-in-pulp system was operated using the lucite Winchester cells on Utex pulp produced by cold leaching. Satisfactory loadings were obtained. (auth)

Development of Programmed Inservice Training on Dialects.

ERIC Educational Resources Information Center

Maxwell, John; And Others

Development of this 6-part inservice program making major use of programed instruction began in 1969 with the objective of modifying classroom teacher behavior in the direction of individualizing the instruction of students learning to control standard English. A review of literature on dialects gave some guidance toward determining the…

Discovering and Analyzing Network Function and Structure

DTIC Science & Technology

2015-07-08

Program Manager currently assigned to the award James Lawton Reporting Period Start Date 04/01/2012 Reporting Period End Date 03/31/2015 Abstract This award...any): Change in AFOSR Program Manager, if any: The program manager is now James Lawton . When this award began, it was Robert Bonneau. Extensions

Entertainment Films and Video in Africa.

ERIC Educational Resources Information Center

Crane, Louise

The film industry in Africa began in 1963. Since then, development has been slow because of funding problems and political restrictions. Television is available to only a fraction of the population and imported programming represents almost one-half of the programming. However, there are some successful African produced television programs. The…

INCREASING DIVERSITY IN ENVIRONMENTAL SCIENCE AND ENGINEERING: THE ORD RESEARCH APPRENTICESHIP PROGRAM FOR HIGH SCHOOL STUDENTS

EPA Science Inventory

The "Research Apprenticeship Program for High School Students" began in 1990 as a collaborative effort between EPA's Office of Research and Development in Research Triangle Park, NC and Shaw University, an Historically Black College/University (HBCU) in Raleigh, NC. The program a...

The Evolution of Electronic Commerce Education

ERIC Educational Resources Information Center

Burkey, Julie

2007-01-01

Business schools began introducing electronic commerce programs in the late 1990s at unprecedented rates. In this study, the author examined the evolution in electronic commerce programs offered by AACSB-accredited colleges and universities from 2001 to 2005. Although these programs are declining in number, they provide the necessary skills and…

Evaluation of a Sandplay Program for Preschoolers in a Multiethnic Neighborhood

ERIC Educational Resources Information Center

Rousseau, Cecile; Benoit, Maryse; Lacroix, Louise; Gauthier, Marie-France

2009-01-01

Background: This evaluative study assesses the efficacy of a school-based secondary prevention program consisting of creative expression workshops for immigrant and refugee preschoolers in a predominantly South Asian multiethnic neighborhood. Coincidentally, the program began in the wake of the tsunami. Method: Pretest and posttest data were…

Immigration: Policy Considerations Related to Guest Worker Programs

DTIC Science & Technology

2010-03-16

The Bracero program , which began during World War II and lasted until 1964, brought several million Mexican agricultural workers into the United...States. At its peak in the late 1950s, the Bracero program employed more than 400,000 Mexican workers annually.1 The Immigration and Nationality Act

The Weekend Intervention Program.

ERIC Educational Resources Information Center

Siegal, Harvey A.

The Weekend Intervention Program (WIP) at the Wright State University School of Medicine is described in this report. Designed to address severe health and social problems while supporting the university's academic mission, the program began with the goal of addressing the health and social problems of alcohol abusers. WIP is a 72-hour intensive…

A Predoctoral Program in Dental Care for the Developmentally Disabled.

ERIC Educational Resources Information Center

Ferguson, Fred S.; And Others

1990-01-01

In 1980, the State University of New York at Stony Brook began a program, integrated into the program of children's dentistry, to train students in care for the developmentally disabled. Management of developmentally disabled patients is provided over three years, and represents an extension of pediatric behavior management. (MSE)

Educating the Learning Disabled Adolescent about Sexuality.

ERIC Educational Resources Information Center

Rothenberg, Gloria S.; And Others

1979-01-01

A sex education program was initiated by the parents of 16 learning disabled young adults. Students' responses to the program varied, reflecting their differences in emotional maturity, intellectual performance, motivation, and social skills. Because of their participation in the program, the parents began to view their children as young adults…

English Camp: A Language Immersion Program in Thailand

ERIC Educational Resources Information Center

Rugasken, Kris; Harris, Jacqueline A.

2009-01-01

A summer English camp language immersion program, which began in 2003, provided instruction by native English speakers to Thai college students via collaboration between Prince of Songkla University in Thailand and Ball State University in Indiana, USA. During this program, Thai students were exposed to English formally through classroom…

Smoking Cessation Failure among Korean Adolescents

ERIC Educational Resources Information Center

Kim, Sung Reul; Kim, Hyun Kyung; Kim, Ji Young; Kim, Hye Young; Ko, Sung Hee; Park, Minyoung

2016-01-01

The aim of this study was to identify smoking cessation failure subgroups among Korean adolescents. Participants were 379 smoking adolescents who joined a smoking cessation program. A questionnaire and a cotinine urine test were administered before the program began. Three months after the program ended, the cotinine urine test was repeated. A…

Evaluating and Selecting Sport Management Undergraduate Programs.

ERIC Educational Resources Information Center

Cuneen, Jacquelyn; Sidwell, M. Joy

1998-01-01

States that the accelerated growth of sport management undergraduate programs that began in the 1980s has continued into the current decade. There are currently 180 sport management major programs in American colleges and universities. Describes the sports management approval process and suggests useful strategies to evaluate sport management…

Participatory Research in an Arts Integration Professional Development Program

ERIC Educational Resources Information Center

Cawthon, Stephanie W.; Dawson, Kathryn M.; Judd-Glossy, Laura; Ihorn, Shasta

2012-01-01

Drama for Schools (DFS) is an arts integration professional development program rooted in critical pedagogy and constructivism that emphasizes partnerships between school districts and a major research university. As a part of the research initiative embedded in this professional development program, DFS began an Arts integration Research Teacher…

Comprehensive evaluation on effective leaching of critical metals from spent lithium-ion batteries.

PubMed

Gao, Wenfang; Liu, Chenming; Cao, Hongbin; Zheng, Xiaohong; Lin, Xiao; Wang, Haijuan; Zhang, Yi; Sun, Zhi

2018-05-01

Recovery of metals from spent lithium-ion batteries (LIBs) has attracted worldwide attention because of issues from both environmental impacts and resource supply. Leaching, for instance using an acidic solution, is a critical step for effective recovery of metals from spent LIBs. To achieve both high leaching efficiency and selectivity of the targeted metals, improved understanding on the interactive features of the materials and leaching solutions is highly required. However, such understanding is still limited at least caused by the variation on physiochemical properties of different leaching solutions. In this research, a comprehensive investigation and evaluation on the leaching process using acidic solutions to recycle spent LIBs is carried out. Through analyzing two important parameters, i.e. leaching speed and recovery rate of the corresponding metals, the effects of hydrogen ion concentration, acid species and concentration on these two parameters were evaluated. It was found that a leachant with organic acids may leach Co and Li from the cathode scrap and leave Al foil as metallic form with high leaching selectivity, while that with inorganic acids typically leach all metals into the solution. Inconsistency between the leaching selectivity and efficiency during spent LIBs recycling is frequently noticed. In order to achieve an optimal status with both high leaching selectivity and efficiency (especially at high solid-to-liquid ratios), it is important to manipulate the average leaching speed and recovery rate of metals to optimize the leaching conditions. Subsequently, it is found that the leaching speed is significantly dependent on the hydrogen ion concentration and the capability of releasing hydrogen ions of the acidic leachant during leaching. With this research, it is expected to improve understanding on controlling the physiochemical properties of a leaching solution and to potentially design processes for spent LIBs recycling with high industrial viability. Copyright © 2018 Elsevier Ltd. All rights reserved.

A two-step leaching method designed based on chemical fraction distribution of the heavy metals for selective leaching of Cd, Zn, Cu, and Pb from metallurgical sludge.

PubMed

Wang, Fen; Yu, Junxia; Xiong, Wanli; Xu, Yuanlai; Chi, Ru-An

2018-01-01

For selective leaching and highly effective recovery of heavy metals from a metallurgical sludge, a two-step leaching method was designed based on the distribution analysis of the chemical fractions of the loaded heavy metal. Hydrochloric acid (HCl) was used as a leaching agent in the first step to leach the relatively labile heavy metals and then ethylenediamine tetraacetic acid (EDTA) was applied to leach the residual metals according to their different fractional distribution. Using the two-step leaching method, 82.89% of Cd, 55.73% of Zn, 10.85% of Cu, and 0.25% of Pb were leached in the first step by 0.7 M HCl at a contact time of 240 min, and the leaching efficiencies for Cd, Zn, Cu, and Pb were elevated up to 99.76, 91.41, 71.85, and 94.06%, by subsequent treatment with 0.2 M EDTA at 480 min, respectively. Furthermore, HCl leaching induced fractional redistribution, which might increase the mobility of the remaining metals and then facilitate the following metal removal by EDTA. The facilitation was further confirmed by the comparison to the one-step leaching method with single HCl or single EDTA, respectively. These results suggested that the designed two-step leaching method by HCl and EDTA could be used for selective leaching and effective recovery of heavy metals from the metallurgical sludge or heavy metal-contaminated solid media.

Recycling of spent lithium-ion battery cathode materials by ammoniacal leaching.

PubMed

Ku, Heesuk; Jung, Yeojin; Jo, Minsang; Park, Sanghyuk; Kim, Sookyung; Yang, Donghyo; Rhee, Kangin; An, Eung-Mo; Sohn, Jeongsoo; Kwon, Kyungjung

2016-08-05

As the production and consumption of lithium ion batteries (LIBs) increase, the recycling of spent LIBs appears inevitable from an environmental, economic and health viewpoint. The leaching behavior of Ni, Mn, Co, Al and Cu from treated cathode active materials, which are separated from a commercial LIB pack in hybrid electric vehicles, is investigated with ammoniacal leaching agents based on ammonia, ammonium carbonate and ammonium sulfite. Ammonium sulfite as a reductant is necessary to enhance leaching kinetics particularly in the ammoniacal leaching of Ni and Co. Ammonium carbonate can act as a pH buffer so that the pH of leaching solution changes little during leaching. Co and Cu can be fully leached out whereas Mn and Al are hardly leached and Ni shows a moderate leaching efficiency. It is confirmed that the cathode active materials are a composite of LiMn2O4, LiCoxMnyNizO2, Al2O3 and C while the leach residue is composed of LiNixMnyCozO2, LiMn2O4, Al2O3, MnCO3 and Mn oxides. Co recovery via the ammoniacal leaching is believed to gain a competitive edge on convenitonal acid leaching both by reducing the sodium hydroxide expense for increasing the pH of leaching solution and by removing the separation steps of Mn and Al. Copyright © 2016 Elsevier B.V. All rights reserved.

An Analysis of Evaluation Plans in a Federally Funded Leadership Preparation Program: Implications for the Improvement of Practice

ERIC Educational Resources Information Center

Sanzo, Karen L.

2012-01-01

This study is a content analysis of selected federally funded leadership preparation program evaluation proposals for the 2008, 2009, and 2010 School Leadership Program grants. The United States Department of Education (USDE) began awarding funding in 2002 to develop and implement preparation programs for aspiring and current assistant principals…

Using a Geriatric Mentoring Narrative Program to Improve Medical Student Attitudes towards the Elderly

ERIC Educational Resources Information Center

Duke, Pamela; Cohen, Diane; Novack, Dennis

2009-01-01

This study examined first-year medical student attitudes concerning the elderly before and after instituting a geriatric mentoring program. The program began and ended with a survey designed to assess students' attitudes toward the elderly. During the mentoring program, students visited the same senior for four visits throughout the academic year.…

Connecticut Sea Grant: Making a Difference. Program Highlights, Accomplishments, and Impacts, 2001-2006

ERIC Educational Resources Information Center

Van Patten, M., Ed.

2007-01-01

The University of Connecticut (UConn) is the formally designated Sea Grant College for the State of Connecticut, serving as the "flagship" university for the Connecticut Sea Grant College Program (CTSG). While a small marine extension program began in 1974 in conjunction with the Cooperative Extension System, the program did not receive…

Bacterial leaching of waste uranium materials.

PubMed

Barbic, F F; Bracilović, D M; Krajincanić, B V; Lucić, J L

1976-01-01

The effect of ferrobacteria and thiobacteria on the leaching of waste uranium materials from which 70-80% of uranium was previously leached by classical chemical hydrometallurgical procedure has been investigated. The bacteria used are found in the ore and the mine water of Zletovska River locality, Yugoslavia. Parameters of biological leaching were examined in the laboratory. Leaching conditions were changed with the aim of increasing the amount of uranium leached. The effect of pyrite added to the waste materials before the beginning of leaching has also been examined. Uranium leaching is directly proportional to the composition and number of ferrobacteria and thiobacteria, and increased by almost twice the value obtained from the same starting materials without using bacteria. Increased sulphuric acid concentrations stimulate considerably the rate of leaching. Uranium leaching is increased up to 20% while sulphuric acid consumption is simultaneously decreased by the addition of pyrite. Uranium concentrations in starting waste materials used for leaching were extremely low (0.0278 and 0.372% U) but about 60% recovery of uranium was obtained, with relatively low consumption of sulphuric acid.

Children Facing Divorce: A Treatment Program

ERIC Educational Resources Information Center

Magid, Kenneth M.

1977-01-01

The children facing divorce program began last year and was built on the talents of an interdisciplinary staff. Included are experts in client-centered counseling, sociometry and psychodrama, Gestalt and TA, behavior modification, and various eclectic approaches to family therapy. (Author)

Stimulating safety culture change in four field demonstration pilots

DOT National Transportation Integrated Search

2010-01-01

Approximately 10 years ago, FRA began investigating organizational culture. Subsequent reorganization of the Volpe Center and HF Program to include Org. Culture & Safety Performance program. This is a summary of FRA field evaluations on the impact of...

Pesticide leaching through sandy and loamy fields - long-term lessons learnt from the Danish Pesticide Leaching Assessment Programme.

PubMed

Rosenbom, Annette E; Olsen, Preben; Plauborg, Finn; Grant, Ruth; Juhler, René K; Brüsch, Walter; Kjær, Jeanne

2015-06-01

The European Union authorization procedure for pesticides includes an assessment of the leaching risk posed by pesticides and their degradation products (DP) with the aim of avoiding any unacceptable influence on groundwater. Twelve-year's results of the Danish Pesticide Leaching Assessment Programme reveal shortcomings to the procedure by having assessed leaching into groundwater of 43 pesticides applied in accordance with current regulations on agricultural fields, and 47 of their DP. Three types of leaching scenario were not fully captured by the procedure: long-term leaching of DP of pesticides applied on potato crops cultivated in sand, leaching of strongly sorbing pesticides after autumn application on loam, and leaching of various pesticides and their DP following early summer application on loam. Rapid preferential transport that bypasses the retardation of the plow layer primarily in autumn, but also during early summer, seems to dominate leaching in a number of those scenarios. Copyright © 2015 Elsevier Ltd. All rights reserved.

Microbiological Leaching of Metallic Sulfides

PubMed Central

Razzell, W. E.; Trussell, P. C.

1963-01-01

The percentage of chalcopyrite leached in percolators by Thiobacillus ferrooxidans was dependent on the surface area of the ore but not on the amount. Typical examples of ore leaching, which demonstrate the role of the bacteria, are presented. In stationary fermentations, changes in KH2PO4 concentration above or below 0.1% decreased copper leaching as did reduction in the MgSO4·7H2O and increase in the (NH4)2SO4 concentration. Bacterial leaching of chalcopyrite was more effective than nonbiological leaching with ferric sulfate; ferric sulfate appeared to retard biological leaching, but this effect was likely caused by formation of an insoluble copper-iron complex. Ferrous sulfate and sodium chloride singly accentuated both bacterial and nonbiological leaching of chalcocite but jointly depressed bacterial action. Sodium chloride appeared to block bacterial iron oxidation without interfering with sulfide oxidation. Bacterial leaching of millerite, bornite, and chalcocite was greatest at pH 2.5. The economics of leaching a number of British Columbia ore bodies was discussed. PMID:16349627

Investigation of the leaching behavior of lead in stabilized/solidified waste using a two-year semi-dynamic leaching test.

PubMed

Xue, Qiang; Wang, Ping; Li, Jiang-Shan; Zhang, Ting-Ting; Wang, Shan-Yong

2017-01-01

Long-term leaching behavior of contaminant from stabilization/solidification (S/S) treated waste stays unclear. For the purpose of studying long-term leaching behavior and leaching mechanism of lead from cement stabilized soil under different pH environment, semi-dynamic leaching test was extended to two years to investigate leaching behaviors of S/S treated lead contaminated soil. Effectiveness of S/S treatment in different scenarios was evaluated by leachability index (LX) and effective diffusion coefficient (D e ). In addition, the long-term leaching mechanism was investigated at different leaching periods. Results showed that no significant difference was observed among the values of the cumulative release of Pb, D e and LX in weakly alkaline and weakly acidic environment (pH value varied from 5.00 to 10.00), and all the controlling leaching mechanisms of the samples immersed in weakly alkaline and weakly acidic environments turned out to be diffusion. Strong acid environment would significantly affect the leaching behavior and leaching mechanism of lead from S/S monolith. The two-year variation of D e appeared to be time dependent, and D e values increased after the 210 th day in weakly alkaline and weakly acidic environment. Copyright © 2016 Elsevier Ltd. All rights reserved.

Leaching of PAHs from agricultural soils treated with oil shale combustion ash: an experimental study.

PubMed

Jefimova, Jekaterina; Adamson, Jasper; Reinik, Janek; Irha, Natalya

2016-10-01

The present study focuses on the fate of polycyclic aromatic hydrocarbons (PAHs) in soils amended with oil shale ash (OSA). Leachability studies to assess the release of PAHs to the environment are essential before the application of OSA in agriculture. A quantitative estimation of the leaching of PAHs from two types of soil and two types of OSA was undertaken in this study. Two leaching approaches were chosen: (1) a traditional one step leaching scheme and (2) a leaching scheme with pretreatment, i.e.., incubation of the material in wet conditions imitating the field conditions, followed by a traditional leaching procedure keeping the total amount of water constant. The total amount of PAHs leached from soil/OSA mixtures was in the range of 15 to 48 μg/kg. The amount of total PAHs leached was higher for the incubation method, compared to the traditional leaching method, particularly for Podzolic Gleysols soil. This suggests that for the incubation method, the content of organic matter and clay minerals of the soil influence the fate of PAHs more strongly compared to the traditional leaching scheme. The amount of PAHs leached from OSA samples is higher than from soil/OSA mixtures, which suggests soils to inhibit the release of PAHs. Calculated amount of PAHs from experimental soil and OSA leaching experiments differed considerably from real values. Thus, it is not possible to estimate the amount of PAHs leached from soil/OSA mixtures based on the knowledge of the amount of PAHs leached from soil and OSA samples separately.

Heavy Metal Leaching as Affected by Long-Time Organic Waste Fertilizer Application.

PubMed

Lekfeldt, Jonas Duus Stevens; Holm, Peter E; Kjærgaard, Charlotte; Magid, Jakob

2017-07-01

The recycling of urban waste products as fertilizers in agriculture may introduce contaminants such as heavy metals into soil that may leach and contaminate groundwater. In the present study, we investigated the leaching of heavy metals from intact soil cores collected in the long-term agricultural field trial CRUCIAL. At the time of sampling, the equivalent of >100 yr of urban waste fertilizers following Danish legislation had been applied. The leaching of Cu was significantly increased in the treatments receiving organic waste products compared with the unfertilized control but remained below the permissible level following Danish drinking water guidelines. The leaching of Cu was controlled primarily by the topsoil Cu content and by the leaching of dissolved organic carbon (DOC) but at the same time significantly correlated with leaching of colloids in soils that had not received fertilizer or had received an organic fertilizer with a low concentration of Cu. The leaching of Zn, Cd, and Co was not significantly increased in urban waste-fertilized treatments. The leaching of Mo was elevated in accelerated waste treatments (both agricultural and urban), and the leaching of Mo was linked to the leaching of DOC. Since leaching of Cr and Pb was strongly linked to the level of colloid leaching, leaching of these metals was reduced in the urban waste treatments. Overall, the results presented should not raise concern regarding the agricultural use of urban waste products in agriculture as long as the relevant guidelines are followed. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Organic reductants based leaching: A sustainable process for the recovery of valuable metals from spent lithium ion batteries.

PubMed

Chen, Xiangping; Guo, Chunxiu; Ma, Hongrui; Li, Jiazhu; Zhou, Tao; Cao, Ling; Kang, Duozhi

2018-05-01

It is significant to recover metal values from spent lithium ion batteries (LIBs) for the alleviation or prevention of potential risks towards environmental pollution and public health, as well as for the conservation of valuable metals. Herein a hydrometallurgical process was proposed to explore the possibility for the leaching of different metals from waste cathodic materials (LiCoO 2 ) of spent LIBs using organics as reductant in sulfuric acid medium. According to the leaching results, about 98% Co and 96% Li can be leached under the optimal experimental conditions of reaction temperature - 95 °C, reaction time - 120 min, reductive agent dosage - 0.4 g/g, slurry density - 25 g/L, concentration of sulfuric acid-3 mol/L in H 2 SO 4  + glucose leaching system. Similar results (96% Co and 100% Li) can be obtained in H 2 SO 4  + sucrose leaching system under optimized leaching conditions. Despite a complete leaching of Li (∼100%), only 54% Co can be dissolved in the H 2 SO 4  + cellulose leaching system under optimized leaching conditions. Finally, different characterization methods, including UV-Vis, FT-IR, SEM and XRD, were employed for the tentative exploration of reductive leaching reactions using organic as reductant in sulfuric acid medium. All the leaching and characterization results confirm that both glucose and sucrose are effective reductants during leaching, while cellulose should be further degraded to organics with low molecular weights to achieve a satisfactory leaching performance. Copyright © 2018 Elsevier Ltd. All rights reserved.

LEACHING BOUNDARY MOVEMENT IN SOLIDIFIED/STABILIZED WASTE FORMS

EPA Science Inventory

Investigation of the leaching of cement-based waste forms in acetic acid solutions found that acids attacked the waste form from the surface toward the center. A sharp leaching boundary was identified in every leached sample, using pH color indica- tors. The movement of the leach...

Abriendo Puertas/Opening Doors Parenting Program: Summary Report of Program Implementation and Impacts. Publication #2014-24

ERIC Educational Resources Information Center

Moore, Kristin A.; Caal, Selma; Lawner, Elizabeth K.; Rojas, Angela; Walker, Karen

2014-01-01

Child Trends conducted a random assignment evaluation of the Abriendo Puertas/Opening Doors program, one of the largest programs in the United States working with low-income Latino parents of children ages zero to five. Since it began in 2007, the program has served over 30,000 parents/families in 34 states. The evaluation study examined the…

Funding and Administrative Coordination of the Baja Field Studies Program at Glendale Community College during the Years 1974 to 1983: A Historical Investigation.

ERIC Educational Resources Information Center

Mercade, Jose A.

Glendale Community College's (GCC's) Baja Field Studies Program began in 1974 as a faculty-initiated overseas field program in marine biology and developed into a college-wide, interdisciplinary program offering different courses under the leadership of a program coordinator. As changes in funding and administration took place due to the altered…

Innovative Approaches to Understanding Transportation/Societal Interactions. Volume 1 : Program Overview and Executive Summaries

DOT National Transportation Integrated Search

1981-10-01

In 1979, the Transportation Systems Center (TSC), under sponsorship of the Urban Mass Transportation Administration (UMTA), began a program of research directed toward improving the understanding of the role of transportation in society, in particula...

Rural Schools and Community Education.

ERIC Educational Resources Information Center

De Largy, Paul

1981-01-01

A community education project in Brooks County, Georgia, began in 1977 with five people, developed county-wide support, and now includes a community education county council, federal funding, volunteer programs, after-school programs, agricultural education (especially swine production), and a day-care center. (AN)

EDTA-assisted leaching of Pb and Cd from contaminated soil.

PubMed

Qiao, Jiangbo; Sun, Huimin; Luo, Xiuhua; Zhang, Wang; Mathews, Shiny; Yin, Xianqiang

2017-01-01

Lead (Pb) and cadmium (Cd) contamination of soil and its harmful effects on human and environmental health have been one concern. In this study, batch and column leaching experiments were conducted to investigate the effects of two EDTA-assisted leaching methods, continuous and intermittent (dry-wet alternate), on the removal of Pb and Cd from contaminated soil. Total content and fractions of Pb and Cd at every 1 cm soil column depth were analyzed before and after the leaching. The results indicated that continuous leaching removed 75.43% of Pb (19.370 mg) and 53.21% of Cd (6.168 mg) and intermittent leaching removed 78.08% of Pb (20.051 mg) and 57.37% of Cd (6.650 mg), which showed intermittent leaching removed more Pb and Cd, but didn't differ significantly (P > 0.05) compared to the continuous leaching. In both leaching methods, total Pb and Cd content in all soil depths reduced after leaching. The two leaching methods made no significant differences in Pb and Cd distributions at different depths of the soil column. Copyright © 2016 Elsevier Ltd. All rights reserved.

Selective leaching of Zn from spent alkaline batteries using environmentally friendly approaches.

PubMed

Maryam Sadeghi, S; Vanpeteghem, Guillaumme; Neto, Isabel F F; Soares, Helena M V M

2017-02-01

The main aim of this work was to evaluate the possibility of using microwave or ultrasound to assist the efficient and selective leaching of Zn from spent alkaline batteries and compare the results with those obtained using the conventional method. Two different strategies were applied: acid leaching of a washed residue and alkaline leaching of the original residue. In both (acid and alkaline) approaches, the use of microwave- or ultrasound-assisted leaching increased the extraction of Zn compared with the best results obtained using conventional leaching [acid leaching (1.5mol/L H 2 SO 4 , 3h, 80°C), 90% of Zn extracted; alkaline leaching (6mol/L NaOH, 3h, 80°C), 42% of Zn extracted]. With acid leaching, 94% of the Zn was extracted using microwave-assisted leaching (1 cycle, 30s, 1mol/L H 2 SO 4 ), and 92% of the Zn was extracted using ultrasound-assisted leaching (2min, 0.1p, 20% amplitude, 1mol/L H 2 SO 4 ). Ultrasound-assisted leaching resulted in a more selective (Zn/Mn ratio of 5.1) Zn extraction than microwave-assisted leaching (Zn/Mn ratio of 3.5); both processes generated a concentrated Zn solution (⩾18.7g/L) with a purity (83.3% and 77.7%, respectively) that was suitable for electrowinning. With alkaline leaching, microwave- (1 cycle, 3 min, 4mol/L NaOH) and ultrasound-assisted (14min, 0.1p, 20% amplitude, 4mol/L NaOH) leaching extracted about 80% of the Zn and less than 0.01% of the Mn, which resulted in lesser concentrated Zn solutions (approximately 16.5g/L) but with high purity (>99.5%) that was suitable for the recovery of Zn by precipitation. The microwave- and ultrasound-assisted leaching strategies used in this work proved to be efficient and environmentally-friendly approaches for the extraction of Zn from spent alkaline residues since a concentrated Zn solution with adequate purity for subsequent Zn recovery was obtained using significantly decreased leaching times and concentrations of chemicals. Copyright © 2017 Elsevier Ltd. All rights reserved.

Fractionation of iron isotopes during leaching of natural particles by acidic and circumneutral leaches and development of an optimal leach for marine particulate iron isotopes

NASA Astrophysics Data System (ADS)

Revels, Brandi N.; Zhang, Ruifeng; Adkins, Jess F.; John, Seth G.

2015-10-01

Iron (Fe) is an essential nutrient for life on land and in the oceans. Iron stable isotope ratios (δ56Fe) can be used to study the biogeochemical cycling of Fe between particulate and dissolved phases in terrestrial and marine environments. We have investigated the dissolution of Fe from natural particles both to understand the mechanisms of Fe dissolution, and to choose a leach appropriate for extracting labile Fe phases of marine particles. With a goal of finding leaches which would be appropriate for studying dissolved-particle interactions in an oxic water column, three particle types were chosen including oxic seafloor sediments (MESS-3), terrestrial dust (Arizona Test Dust - A2 Fine), and ocean sediment trap material from the Cariaco basin. Four leaches were tested, including three acidic leaches similar to leaches previously applied to marine particles and sediments (25% acetic acid, 0.01 N HCl, and 0.5 N HCl) and a pH 8 oxalate-EDTA leach meant to mimic the dissolution of particles by organic complexation, as occurs in natural seawater. Each leach was applied for three different times (10 min, 2 h, 24 h) at three different temperatures (25 °C, 60 °C, 90 °C). MESS-3 was also leached under various redox conditions (0.02 M hydroxylamine hydrochloride or 0.02 M hydrogen peroxide). For all three sample types tested, we find a consistent relationship between the amount of Fe leached and leachate δ56Fe for all of the acidic leaches, and a different relationship between the amount of Fe leached and leachate δ56Fe for the oxalate-EDTA leach, suggesting that Fe was released through proton-promoted dissolution for all acidic leaches and by ligand-promoted dissolution for the oxalate-EDTA leach. Fe isotope fractionations of up to 2‰ were observed during acidic leaching of MESS-3 and Cariaco sediment trap material, but not for Arizona Test Dust, suggesting that sample composition influences fractionation, perhaps because Fe isotopes are greatly fractionated during leaching of silicates and clays but only minimally fractionated during dissolution of Fe oxyhydroxides. Two different analytical models were developed to explain the relationship between amount of Fe leached and δ56Fe, one of which assumes mixing between two Fe phases with different δ56Fe and different dissolution rates, and the other of which assumes dissolution of a single phase with a kinetic isotope effect. We apply both models to fit results from the acidic leaches of MESS-3 and find that the fit for both models is very similar, suggesting that isotope data will never be sufficient to distinguish between these two processes for natural materials. Next, we utilize our data to choose an optimal leach for application to marine particles. The oxalate-EDTA leach is well-suited to this purpose because it does not greatly fractionate Fe isotopes for a diversity of particle types over a wide variety of leaching conditions, and because it approximates the conditions by which particulate Fe dissolves in the oceans. We recommend a 2 h leach at 90 °C with 0.1 M oxalate and 0.05 M EDTA at pH 8 to measure labile ;ligand-leachable; particulate δ56Fe on natural marine materials with a range of compositions.

U.S. Information Ambassadors: The Library/Book Fellows Program.

ERIC Educational Resources Information Center

Doyle, Robert P.

The Library/Book Fellows Program began in 1986 with a grant to the American Library Association from the U.S. Information Agency, an independent agency within the Executive Branch. The purposes of the program are to: (1) increase international understanding through the establishment of professional and personal relationships and the accomplishment…

A Qualitative Study on Transferring the Experience of Using Technology from Formal Education to Distance Education

ERIC Educational Resources Information Center

Yildiz, Merve; Selim, Yavuz

2015-01-01

With improvements in information technologies, distance education programs have become widespread. Institutions that offer distance education programs are increasing in number. Scholars who were used to face-to-face teaching began to give courses in distance education programs which entail technological teaching methods, a new teaching experience…

Preparing for the Profession: The Accounting Job Search and Beyond

ERIC Educational Resources Information Center

Landgraf, Ellen L.; Stanko, Brian B.; Jinkerson, Darcia

2012-01-01

This paper provides a detailed description of a unique program focused on preparing students for entry into the accounting profession. The program, Preparing for the Profession, consisted of four distinct workshops provided to accounting majors during fall semester 2010. Planning for the program began a year earlier during a meeting of Accounting…

Human Spaceflight and American Society: The Record So Far

NASA Technical Reports Server (NTRS)

Murray, Charles

2005-01-01

This paper presents a look at the historical Apollo Program and it's comparisons to NASA's human spaceflight program today. The author gives three examples of how audacity began with the Apollo Program and explains how human spaceflight must continue with this audacity to do new things and take on large missions.

Using Research to Design Integrated Education and Training Programs

ERIC Educational Resources Information Center

Pappalardo, Michele; Schaffer, William R.

2016-01-01

With the passage of the Workforce Innovation and Opportunity Act (WIOA) of 2014, Northampton Community College began the creation of Integrated Education and Training (IE&T) programs in October 2015. After a needs assessment was conducted with the partners, programs were created to address the needs in the hospitality and healthcare sectors.…

Enacting the Independent Public Schools Program in Western Australia

ERIC Educational Resources Information Center

Gobby, Brad

2013-01-01

The Independent Public Schools (IPS) program began to be implemented in some Western Australian schools in 2010. The IPS program devolves a number of responsibilities to principals and is part of the political objective of removing the constraints of the education bureaucracy by fostering school level decision-making, problem-solving and…

A Model for Differentiation of Adjunct Faculty. Techniques.

ERIC Educational Resources Information Center

Paprock, Kenneth E.

1987-01-01

The Regis Career Education Program (RECEP) is an accelerated degree-granting program for adults at Regis College in Denver, Colorado. Since the program began in 1979, there has been a steady increase in enrollments and, consequently, a steady increase in the number of adjunct faculty. These adjunct faculty members are generally drawn from outside…

78 FR 54510 - New Entrant Safety Assurance Program Operational Test

Federal Register 2010, 2011, 2012, 2013, 2014

2013-09-04

...-0298] New Entrant Safety Assurance Program Operational Test AGENCY: Federal Motor Carrier Safety...) announces an operational test of procedural changes to the New Entrant Safety Assurance Program. The operational test began in July 2013 and will be in effect for up to 12 months. It is applicable to new entrant...

TTIP Texas Teacher Internship Program: 1996 Curriculum Implementation Plans.

ERIC Educational Resources Information Center

Walenta, Brian T., Ed.

In 1989, the Texas Alliance for Science, Technology, and Mathematics Education began placing teachers at industry sites as part of its Texas Teacher Internship Program (TTIP). TTIP is a competitive program for science, technology, and mathematics teachers who serve as summer interns at industry and university sites in order to experience…

Peterson's Guide to Colleges with Programs for Learning-Disabled Students.

ERIC Educational Resources Information Center

Mangrum, Charles T., II, Ed.; Strichart, Stephen S., Ed.

A guide to 279 college and universities offering full-service programs for students with dyslexia and other learning disabilities (LDs) is presented. An introductory section discusses what LDs are, what college students with LDs are like, why colleges began providing programs for these students, admissions and support after admission, and how high…

Oak restoration trials: Santa Catalina Island

Treesearch

Lisa Stratton

2002-01-01

Two restoration trials involving four oak species have been implemented as part of a larger restoration program for Catalina Island. In 1997 the Catalina Island Conservancy began an active program of restoration after 50 years of ranching and farming activities on the island. The restoration program includes removing feral goats and pigs island-wide and converting 80...

Expanding Access and Opportunity: The Impact of the Gates Millennium Scholars Program

ERIC Educational Resources Information Center

Ramsey, Jennifer

2010-01-01

In 1999, the Bill & Melinda Gates Foundation began an innovative scholarship program that provides full financial support to low-income minority students across the United States. The Gates Millennium Scholars (GMS) program has already awarded more than 10,000 scholarships to exceptional students, with the ultimate goal of funding at least…

Keeping Our Students in School: An Alternative Approach for At-Risk Students.

ERIC Educational Resources Information Center

Steinmiller, Georgine G.; Steinmiller, Robert

This paper describes a dropout prevention, residential summer program on university campuses in Arkansas. The Youth Opportunities Unlimited (YOU) progam began in 1988 at Henderson State University and by 1990 five Arkansas universities hosted programs. Funds for the program are provided through state agencies, the universities, vocational funds,…

Civic Engagement: A Pathway to Service and Learning

ERIC Educational Resources Information Center

Garcia, Rudy

2004-01-01

This article features a service learning program at Albuquerque TVI Community College which provides hands-on civic education to its students. The Service Learning Program began in 1994 with a $5,000 grant from the American Association of Community Colleges (AACC). The success of the program provided for the development of the Department of…

State of Supported Nickel Nanoparticles during Catalysis in Aqueous Media

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chase, Zizwe; Kasakov, Stanislav; Shi, Hui

2015-11-09

The state of Ni supported on HZSM-5 zeolite, silica, and sulfonated carbon was determined during aqueous phase catalysis of phenol hydrodeoxygenation using in situ extended X-ray absorption fine structure spectroscopy (EXAFS). On sulfonated carbon and HZSM-5 supports, the NiO and Ni(OH)2 were readily reduced to Ni(0) under reaction conditions (~35 bar H2 in aqueous phenol solutions containing up to 0.5 wt. % phosphoric acid at 473 K). On the silica support, less than 70% of the Ni was converted to Ni(0) under reaction conditions, which is attributed to the formation of Ni phyllosilicates. Over a broad range of reaction conditionsmore » there was no leaching of Ni from the supports. In contrast, rapid leaching of the Ni(II) from HZSM-5 was observed, when 15 wt. % aqueous acetic acid was substituted for the aqueous phenol solution. Once the metallic state of Ni was established there was no leaching in 15 wt. % acetic acid at 473 K and 35 bar H2. This work was supported by the U.S. Department of Energy (DOE), Office of Science, Office of Basic Energy Sciences (BES), Division of Chemical Sciences, Geosciences & Biosciences. The STEM was supported under the Laboratory Directed Research and Development Program: Chemical Imaging Initiative at Pacific Northwest National Laboratory (PNNL), a multi-program national laboratory operated for DOE by Battelle under Contract DE-AC05-76RL01830. STEM was performed at EMSL, a DOE Office of Science user facility sponsored by the Office of Biological and Environmental Research and located at PNNL.« less

Chapter 14. New tools to assess nitrogen management for conservation of our biosphere

USDA-ARS?s Scientific Manuscript database

There are several tools that can be used to assess the effects of management on nitrogen (N) losses to the environment. The Nitrogen Loss and Environmental Assessment Package (NLEAP) is an improved and renamed version of the DOS program that was called the Nitrate Leaching and Economic Analysis Pack...

Ceramics in nuclear waste management

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chikalla, T D; Mendel, J E

1979-05-01

Seventy-three papers are included, arranged under the following section headings: national programs for the disposal of radioactive wastes, waste from stability and characterization, glass processing, ceramic processing, ceramic and glass processing, leaching of waste materials, properties of nuclear waste forms, and immobilization of special radioactive wastes. Separate abstracts were prepared for all the papers. (DLC)

Ecological Research Division Theoretical Ecology Program. [Contains abstracts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1990-10-01

This report presents the goals of the Theoretical Ecology Program and abstracts of research in progress. Abstracts cover both theoretical research that began as part of the terrestrial ecology core program and new projects funded by the theoretical program begun in 1988. Projects have been clustered into four major categories: Ecosystem dynamics; landscape/scaling dynamics; population dynamics; and experiment/sample design.

Rewetting effects on soil CO2 flux and nutrients leaching in alpine Kobresia pasture on the Tibetan Plateau

NASA Astrophysics Data System (ADS)

Liu, Shibin; Schleuss, Per; Kuzyakov, Yakov

2015-04-01

Kobresia pygmaea pastures of the Tibetan Plateau are one of the most important ecosystems around the world due to its large grazing area and very high soil organic carbon storage. Since the last decades grasslands of the TP are highly affected by grassland degradation because of various sedimentary programs and strongly increase grazing pressure. Climate changes (e.g. increased precipitation and temperature) may accelerate this degradation processes by enhancing soil organic matter mineralization and nutrients leaching. We exposed repeated rewetting cycles to test the effects of increased precipitation frequency on CO2 fluxes and leaching on varying K. pygmaea root mats (including: intact root mats (KL); recently died root mats (KD); crust covered root mats (LI)). Two phases were conducted (a) to identify the response of nighttime CO2 flux to changing soil moisture and (b) to investigate the impacts of rewetting cycles on day-, night-, and full day CO2 fluxes together with leaching of carbon (C) and nitrogen (N). Nighttime CO2 fluxes correlated positively with soil moisture, indicating that increasing precipitation will accelerate SOC losses due to increasing mineralization rates. KD showed highest C losses as CO2 efflux and also the highest leaching compared to KL and LI. It indicates that dying of Kobresia root mats (as induced by overgrazing and continuously removal of photosynthetically active shoot biomass) will rapidly decrease SOC storage. The lowest C losses (from soil respiration and DOC leaching) were obtained in the crust covered root mats (LI), because most C losses have already occurred during the early period. Highest N losses (especially NO3-) were obtained in the highly degraded pasture (LI). Due to long-term SOM decomposition of crust covered root mats (LI) in situ, inorganic nitrogen (NO3-) was accumulated in and was leached out during the first rewetting cycles. In contrast, no losses of NH4+ and NO3- occurred for intact Kobresia root mats (KL), because the plants took up mineral nitrogen. These results were consistent to very low C/N ratios of leachates in crust-covered root mats. The low C/N ratio in LI was mainly connected by nitrogen accumulation before leaching, whereas the slightly lower C/N ratio in KD was mainly affected by carbon losses (DOC) due to increased SOM decomposition. This study indicates that in combination overgrazing and precipitation change might strongly reduce SOC storage. Furthermore, the high nutrient losses after initial degradation of these N and P limited grasslands might have dramatic consequences for this ecosystem. Therefore, saving and restoration of natural vegetation cover by decreasing grazing intensities is the only strategy to maintain soil fertility and protect Kobresia ecosystems against degradation.

Leaching of TCIPP from furniture foam is rapid and substantial.

PubMed

Stubbings, William A; Harrad, Stuart

2018-02-01

A series of laboratory experiments were conducted, in which waste furniture polyurethane foam samples containing tris (1-chloro-2-propyl) phosphate (TCIPP) were contacted with a range of leaching fluids, formulated to simulate the composition of landfill leachate. Leaching was examined under a number of different scenarios, such as: dissolved humic matter concentration, pH, and temperature, as well as the effect of agitation, and waste:leaching fluid contact duration. In addition to single batch (no replenishment of leaching fluid), serial batch (draining of leachate and replenishment with fresh leaching fluid at various time intervals) experiments were conducted. Leaching of TCIPP from PUF appears to be a first order process. Concentrations of TCIPP in leachate generated by the experiments in this study ranged from 13 mg L -1 to 130 mg L -1 . In serial batch leaching experiments, >95% of TCIPP was depleted from PUF after 168 h total contact with leaching fluid. Our experiments indicate leaching is potentially a very significant pathway of TCIPP emissions to the environment. Copyright © 2017. Published by Elsevier Ltd.

Increasing flux rate to shorten leaching period and ramp-up production

NASA Astrophysics Data System (ADS)

Ngantung, Billy; Agustin, Riska; Ravi'i

2017-01-01

J Resources Bolaang Mongondow (JBRM) has operated a dynamic heap leach in its Bakan Gold Mine since late 2013. After successfully surpassing its name plate capacity of 2.6 MT/annum in 2014, the clayey and transition ore become the next operational challenge. The presence of transition and clayey ore requires longer leaching period, hence reducing the leach pad capacity which then caused reduced production. Maintaining or even increasing production with such longer leaching ore types can be done by expanding the leach pad area which means an additional capital investment, and/or shortening the leaching cycle which compromise a portion of gold extraction. JBRM has been successfully increasing the leach pad production from 2.6 MT/annum to 3.8 MT/annum, whilst improving the gold extraction from around 70% to around 80%. This was achieved by managing the operation of the leach pad which is shortening the leach cycle by identifying and combining the optimal flux rate application versus the tonne processed in each cell, at no capital investment for expanding the cell capacity.

RESEARCH APPRENTICESHIP PROGRAM FOR HIGH SCHOOL STUDENTS

EPA Science Inventory

The Research Apprenticeship Program began in 1990 as a collaborative effort between EPA's Office of Research and Development in Research Triangle Park, NC and Shaw University in Raleigh, NC to address the under representation of minorities in the fields of science and engineering...

Leaching of DOC, DN, and inorganic constituents from scrap tires.

PubMed

Selbes, Meric; Yilmaz, Ozge; Khan, Abdul A; Karanfil, Tanju

2015-11-01

One concern for recycle and reuse of scrap tires is the leaching of tire constituents (organic and inorganic) with time, and their subsequent potential harmful impacts in environment. The main objective of this study was to examine the leaching of dissolved organic carbon (DOC), dissolved nitrogen (DN), and selected inorganic constituents from scrap tires. Different sizes of tire chips and crumb rubber were exposed to leaching solutions with pH's ranging from 3.0 to 10.0 for 28days. The leaching of DOC and DN were found to be higher for smaller size tire chips; however, the leaching of inorganic constituents was independent of the size. In general, basic pH conditions increased the leaching of DOC and DN, whereas acidic pH conditions led to elevated concentrations of metals. Leaching was minimal around the neutral pH values for all the monitored parameters. Analysis of the leaching rates showed that components associated with the rubbery portion of the tires (DOC, DN, zinc, calcium, magnesium, etc.) exhibited an initial rapid followed by a slow release. On the other hand, a constant rate of leaching was observed for iron and manganese, which are attributed to the metal wires present inside the tires. Although the total amounts that leached varied, the observed leaching rates were similar for all tire chip sizes and leaching solutions. Operation under neutral pH conditions, use of larger size tire chips, prewashing of tires, and removal of metal wires prior to application will reduce the impact of tire recycle and reuse. Copyright © 2015 Elsevier Ltd. All rights reserved.

Leaching characteristics of arsenic and selenium from coal fly ash: role of calcium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tian Wang; Jianmin Wang; Yulin Tang

2009-05-15

Understanding the leaching behavior of arsenic (As) and selenium (Se) in coal fly ash is important in evaluating the potential environmental impact of coal fly ash. Batch experiments were employed to systematically investigate the leaching behavior of As and Se in two major types of coal fly ashes, bituminous coal ash and sub-bituminous coal ash, and to determine the underlying processes that control As and Se leaching. The effects of pH, solid/liquid (S/L) ratio, calcium addition, and leaching time on the release of As and Se were studied. Overall, bituminous coal ash leached significantly more As and Se than sub-bituminousmore » coal ash, and Se was more readily leachable, in both absolute concentration and relative fraction, than As for both types of fly ashes. Adsorption/desorption played a major role on As and Se leaching from bituminous coal ashes. However, calcium precipitation played the most important role in reducing As and Se leaching from sub-bituminous coal ashes in the entire experimental pH range. The leaching of As and Se from bituminous coal ashes generally increased with increases in the S/L ratio and leaching time. However, for sub-bituminous coal ashes, the leaching of As was not detected under most experimental conditions, while the leaching of Se increased with increases in the S/L ratio and leaching time. As{sup V} and Se{sup IV} were found to be the major species in all ash leachates in this study. 46 refs., 7 figs., 1 tab.« less

Preparation of Rutile from Ilmenite Concentrate Through Pressure Leaching with Hydrochloric Acid

NASA Astrophysics Data System (ADS)

Xiang, Junyi; Liu, Songli; Lv, Xuewei; Bai, Chenguang

2017-04-01

Take into account the fact that the natural rutile utilized for the production of titanium dioxide pigment through chloride process is desperately lacking worldwide especially in China, an attempt was exploited for extracting synthetic rutile from Yunnan ilmenite concentrate with hydrochloric acid pressure leaching process. The leaching parameters for one step leaching process were investigated. The results shown that the optimum condition is leaching temperature of 413 K (140 °C), acid concentration of 20 pct HCl, leaching time of 4 hours and liquid/solid mass ratio of 8:1. A two steps leaching process was also suggested to reutilize the leaching liquor which with a high content of HCl. The results showed that the content of HCl decreased from 135 to 75 g/L, total iron increased from 44.5 g/L to about 87.6 g/L, and the liquid/solid mass ratio decreased to 5:1 with a two steps leaching process. The leaching product produced through a two steps leaching process shows a pure golden red with a high content of titanium (92.65 pct TiO2), a relatively low content of calcium (0.10 pct CaO) and magnesium (0.12 pct MgO), but high content of silicon (5.72 pct SiO2).

Comparison of ultrasound-assisted and traditional caustic leaching of spent cathode carbon (SCC) from aluminum electrolysis.

PubMed

Xiao, Jin; Yuan, Jie; Tian, Zhongliang; Yang, Kai; Yao, Zhen; Yu, Bailie; Zhang, Liuyun

2018-01-01

The spent cathode carbon (SCC) from aluminum electrolysis was subjected to caustic leaching to investigate the different effects of ultrasound-assisted and traditional methods on element fluorine (F) leaching rate and leaching residue carbon content. Sodium hydroxide (NaOH) dissolved in deionized water was used as the reaction system. Through single-factor experiments and a comparison of two leaching techniques, the optimum F leaching rate and residue carbon content for ultrasound-assisted leaching process were obtained at a temperature of 70°C, residue time of 40min, initial mass ratio of alkali to SCC (initial alkali-to-material ratio) of 0.6, liquid-to-solid ratio of 10mL/g, and ultrasonic power of 400W, respectively. Under the optimal conditions, the leaching residue carbon content was 94.72%, 2.19% larger than the carbon content of traditional leaching residue. Leaching wastewater was treated with calcium chloride (CaCl 2 ) and bleaching powder and the treated wastewater was recycled caustic solution. All in all, benefiting from advantage of the ultrasonication effects, ultrasound-assisted caustic leaching on spent cathode carbon had 55.6% shorter residue time than the traditional process with a higher impurity removal rate. Copyright © 2017 Elsevier B.V. All rights reserved.

Melter Feed Reactions at T ≤ 700°C for Nuclear Waste Vitrification

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xu, Kai; Hrma, Pavel R.; Rice, Jarrett A.

2015-07-23

Batch reactions and phase transitions in a nuclear waste feed heated at 5 K min-1 up to 600°C were investigated by optical microscopy, scanning electron microscopy with energy dispersive X-ray spectrometer, and X-ray diffraction. Quenched samples were leached in deionized water at room temperature and 80°C to extract soluble salts and early glass-forming melt, respectively. To determine the content and composition of leachable phases, the leachates were analyzed by the inductively-coupled plasma spectroscopy. By ~400°C, gibbsite and borax lost water and converted to amorphous and intermediate crystalline phases. Between 400°C and 600°C, the sodium borate early glass-forming melt reacted withmore » amorphous aluminum oxide and calcium oxide to form intermediate products containing Al and Ca. At ~600°C, half Na and B converted to the early glass-forming melt, and quartz began to dissolve in the melt.« less

Leaching boundary movement in solidified/stabilized waste forms

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kuang Ye Cheng; Bishop, P.L.

1992-02-01

Investigation of the leaching of cement-based waste forms in acetic acid solutions found that acids attacked the waste form from the surface toward the center. A sharp leaching boundary was identified in every leached sample, using pH color indicators. The movement of the leaching boundary was found to be a single diffusion-controlled process.

Application of municipal biosolids to dry-land wheat fields - A monitoring program near Deer Trail, Colorado (USA). A presentation for an international conference: "The Future of Agriculture: Science, Stewardship, and Sustainability", August 7-9, 2006, Sacramento, CA

USGS Publications Warehouse

Crock, James G.; Smith, David B.; Yager, Tracy J.B.

2006-01-01

Since late 1993, Metro Wastewater Reclamation District of Denver (Metro District), a large wastewater treatment plant in Denver, Colorado, has applied Grade I, Class B biosolids to about 52,000 acres of non-irrigated farmland and rangeland near Deer Trail, Colorado. In cooperation with the Metro District in 1993, the U.S. Geological Survey (USGS) began monitoring ground water at part of this site. In 1999, the USGS began a more comprehensive study of the entire site to address stakeholder concerns about the chemical effects of biosolids applications. This more comprehensive monitoring program has recently been extended through 2010. Monitoring components of the more comprehensive study included biosolids collected at the wastewater treatment plant, soil, crops, dust, alluvial and bedrock ground water, and stream bed sediment. Streams at the site are dry most of the year, so samples of stream bed sediment deposited after rain were used to indicate surface-water effects. This presentation will only address biosolids, soil, and crops. More information about these and the other monitoring components are presented in the literature (e.g., Yager and others, 2004a, b, c, d) and at the USGS Web site for the Deer Trail area studies at http://co.water.usgs.gov/projects/CO406/CO406.html. Priority parameters identified by the stakeholders for all monitoring components, included the total concentrations of nine trace elements (arsenic, cadmium, copper, lead, mercury, molybdenum, nickel, selenium, and zinc), plutonium isotopes, and gross alpha and beta activity, regulated by Colorado for biosolids to be used as an agricultural soil amendment. Nitrogen and chromium also were priority parameters for ground water and sediment components. In general, the objective of each component of the study was to determine whether concentrations of priority parameters (1) were higher than regulatory limits, (2) were increasing with time, or (3) were significantly higher in biosolids-applied areas than in a similar farmed area where biosolids were not applied. Where sufficient samples could be collected, statistical methods were used to evaluate effects. Rigorous quality assurance was included in all aspects of the study. The roles of hydrology and geology also were considered in the design, data collection, and interpretation phases of the study. Study results indicate that the chemistry of the biosolids from the Denver plant was consistent during 1999-2005, and total concentrations of regulated trace elements were consistently lower than the regulatory limits. Plutonium isotopes were not detected in the biosolids. Leach tests using deionized water to simulate natural precipitation indicate arsenic, molybdenum, and nickel were the most soluble priority parameters in the biosolids. Study results show no significant difference in concentrations of priority parameters between biosolids-applied soils and unamended soils where no biosolids were applied. However, biosolids were applied only twice during 1999-2003. The next soil sampling is not scheduled until 2010. To date concentrations of most of the priority parameters were not much greater in the biosolids than in natural soil from the sites. Therefore, many more biosolids applications would need to occur before biosolids effects on the soil priority constituents can be quantified. Leach tests using deionized water to simulate precipitation indicate that molybdenum and selenium were the priority parameters that were most soluble in both biosolids-applied soil and natural or unamended soil. Study results do not indicate significant differences in concentrations of priority parameters between crops grown in biosolids-applied areas and crops grown where no biosolids were applied. However, crops were grown only twice during 1999-2003, so only two crop samples could be collected. The wheat-grain elemental data collected during 1999-2003 for both biosolids-applied areas and unamended areas are similar

Activities of the National Water-Quality Assessment Program in the upper Snake River Basin, Idaho and western Wyoming, 1991-2001

USGS Publications Warehouse

Low, Walton H.

1997-01-01

In 1991, the U.S. Geological Survey (USGS) began a full-scale National Water-Quality Assessment (NAWQA) Program. The long-term goals of the NAWQA Program are to describe the status and trends in the water quality of a large part of the Nation's rivers and aquifers and to improve understanding of the primary natural and human factors that affect water-quality conditions. In meeting these goals, the program will produce water-quality, ecological, and geographic information that will be useful to policy makers and managers at the national, State, and local levels. A major component of the program is study-unit investigations, upon which national-level assessment activities are based. The program's 60 study-unit investigations are associated with principal river basins and aquifer systems throughout the Nation. Study units encompass areas from 1,200 to more than 65,000 mi2 (square miles) and incorporate about 60 to 70 percent of the Nation's water use and population served by public water supply. In 1991, the upper Snake River Basin was among the first 20 NAWQA study units selected for implementation. From 1991 to 1995, a high-intensity data-collection phase of the upper Snake River Basin study unit (fig. 1) was implemented and completed. Components of this phase are described in a report by Gilliom and others (1995). In 1997, a low-intensity phase of data collection began, and work continued on data analysis, report writing, and data documentation and archiving activities that began in 1996. Principal data-collection activities during the low-intensity phase will include monitoring of surface-water and ground-water quality, assessment of aquatic biological conditions, and continued compilation of environmental setting information.

Kennedy Space Center exercise program

NASA Technical Reports Server (NTRS)

Hoffman, Cristy

1993-01-01

The Kennedy Space Center (KSC) Fitness Program began in Feb. 1993. The program is managed by the Biomedical Operations and Research Office and operated by the Bionetics Corporation. The facilities and programs are offered to civil servants, all contractors, temporary duty assignment (TDY) participants, and retirees. All users must first have a medical clearance. A computer-generated check-in system is used to monitor participant usage. Various aspects of the program are discussed.

Leaching of metals from large pieces of printed circuit boards using citric acid and hydrogen peroxide.

PubMed

Jadhav, Umesh; Su, C; Hocheng, Hong

2016-12-01

In the present study, the leaching of metals from large pieces of computer printed circuit boards (CPCBs) was studied. A combination of citric acid (0.5 M) and 1.76 M hydrogen peroxide (H 2 O 2 ) was used to leach the metals from CPCB piece. The influence of system variables such as H 2 O 2 concentration, concentration of citric acid, shaking speed, and temperature on the metal leaching process was investigated. The complete metal leaching was achieved in 4 h from a 4 × 4 cm CPCB piece. The presence of citric acid and H 2 O 2 together in the leaching solution is essential for complete metal leaching. The optimum addition amount of H 2 O 2 was 5.83 %. The citric acid concentration and shaking speed had an insignificant effect on the leaching of metals. The increase in the temperature above 30 °C showed a drastic effect on metal leaching process.

Leaching Behavior of Heavy Metals from Cement Pastes Using a Modified Toxicity Characteristic Leaching Procedure (TCLP).

PubMed

Huang, Minrui; Feng, Huajun; Shen, Dongsheng; Li, Na; Chen, Yingqiang; Shentu, Jiali

2016-03-01

As the standard toxicity characteristic leaching procedure (TCLP) can not exhaust the acid neutralizing capacity of the cement rotary kiln co-processing solid wastes products which is particularly important for the assessment of the leaching concentrations of heavy metals. A modified TCLP was proposed. The extent of leaching of heavy metals is low using the TCLP and the leaching performance of the different metals can not be differentiated. Using the modified TCLP, however, Zn leaching was negligible during the first 180 h and then sharply increased (2.86 ± 0.18 to 3.54 ± 0.26 mg/L) as the acidity increased (pH < 6.0). Thus, Zn leaching is enhanced using the modified TCLP. While Pb leached readily during the first 126 h and then leachate concentrations decreased to below the analytical detection limit. To conclude, this modified TCLP is a more suitable method for these cement rotary kiln co-processing products.

Gold Leaching Characteristics and Intensification of a High S and As-Bearing Gold Concentrate

NASA Astrophysics Data System (ADS)

Yang, Yong-bin; Liu, Xiao-liang; Jiang, Tao; Li, Qian; Xu, Bin; Zhang, Yan

Some high sulfur and arsenic-bearing gold concentrate has a gold leaching rate less than 80% by oxidation roasting-pickling-cyanidation process. The characteristics and intensification of gold leaching were studied systemically. By combining chemical composition and phase analysis, the low gold leaching rate was found to lie in the capsulation of gold by iron-containing phases including iron oxides, arsenopyrite and pyrite. 96.66% of gold in the industrial leaching residue was capsulated and 95.88% of the capsulated turned out to be in the iron-containing phases. The results of laboratory pickling-cyanidation experiments on the calcine and industrial leaching residue presented further demonstration for the fact that gold capsulated in the iron-containing phases was hard to be leached. However, the gold cyanide leaching rate of calcine could be raised over 95% by a reduction roasting-pickling pretreatment which played such a significant role in exposing the capsulated gold that gold leaching was intensified remarkably.

Experimental and numerical analysis of metal leaching from fly ash-amended highway bases

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cetin, Bora; Aydilek, Ahmet H., E-mail: aydilek@umd.edu; Li, Lin

2012-05-15

Highlights: Black-Right-Pointing-Pointer This study is the evaluation of leaching potential of fly ash-lime mixed soils. Black-Right-Pointing-Pointer This objective is met with experimental and numerical analysis. Black-Right-Pointing-Pointer Zn leaching decreases with increase in fly ash content while Ba, B, Cu increases. Black-Right-Pointing-Pointer Decrease in lime content promoted leaching of Ba, B and Cu while Zn increases. Black-Right-Pointing-Pointer Numerical analysis predicted lower field metal concentrations. - Abstract: A study was conducted to evaluate the leaching potential of unpaved road materials (URM) mixed with lime activated high carbon fly ashes and to evaluate groundwater impacts of barium, boron, copper, and zinc leaching. Thismore » objective was met by a combination of batch water leach tests, column leach tests, and computer modeling. The laboratory tests were conducted on soil alone, fly ash alone, and URM-fly ash-lime kiln dust mixtures. The results indicated that an increase in fly ash and lime content has significant effects on leaching behavior of heavy metals from URM-fly ash mixture. An increase in fly ash content and a decrease in lime content promoted leaching of Ba, B and Cu whereas Zn leaching was primarily affected by the fly ash content. Numerically predicted field metal concentrations were significantly lower than the peak metal concentrations obtained in laboratory column leach tests, and field concentrations decreased with time and distance due to dispersion in soil vadose zone.« less

Environmental implications of material leached from coal.

PubMed

Moyo, Stanley; Mujuru, Munyaradzi; McCrindle, Rob I; Mokgalaka-Matlala, Ntebogeng

2011-05-01

Samples of coal were collected from different seams at a South African coal mine and comparative leaching experiments were carried out under various pH conditions and times to investigate the leaching behavior and potential environmental impact of possibly hazardous elements such as As, Cd, Co, Cr, Mn, Ni, Pb, Th and U. The calculated leaching intensities, sequential extraction results and cumulative percentages demonstrate that the leaching behavior of the elements is strongly influenced by the pH, the leaching time and the properties and occurrences of the elements. The leached concentrations of As, Cd, Co, Cr, Mn, Ni and Pb exceeded the maximum concentrations recommended by the Environmental Protection Agency (EPA) for surface water.

Protocols for collection of streamflow, water-quality, streambed-sediment, periphyton, macroinvertebrate, fish, and habitat data to describe stream quality for the Hydrobiological Monitoring Program, Equus Beds Aquifer Storage and Recovery Program, city of Wichita, Kansas

USGS Publications Warehouse

Stone, Mandy L.; Rasmussen, Teresa J.; Bennett, Trudy J.; Poulton, Barry C.; Ziegler, Andrew C.

2012-01-01

The city of Wichita, Kansas uses the Equus Beds aquifer, one of two sources, for municipal water supply. To meet future water needs, plans for artificial recharge of the aquifer have been implemented in several phases. Phase I of the Equus Beds Aquifer Storage and Recovery (ASR) Program began with injection of water from the Little Arkansas River into the aquifer for storage and subsequent recovery in 2006. Construction of a river intake structure and surface-water treatment plant began as implementation of Phase II of the Equus Beds ASR Program in 2010. An important aspect of the ASR Program is the monitoring of water quality and the effects of recharge activities on stream conditions. Physical, chemical, and biological data provide the basis for an integrated assessment of stream quality. This report describes protocols for collecting streamflow, water-quality, streambed-sediment, periphyton, macroinvertebrate, fish, and habitat data as part of the city of Wichita's hydrobiological monitoring program (HBMP). Following consistent and reliable methods for data collection and processing is imperative for the long-term success of the monitoring program.

Impacts of road salts on leaching behavior of lead contaminated soil.

PubMed

Wu, Jingjing; Kim, Hwidong

2017-02-15

Research was conducted to explore the effects of road salts on lead leaching from lead contaminated soil samples that were collected in an old residence area in Erie, PA. The synthetic precipitate leaching procedure (SPLP) test was employed to evaluate lead leaching from one of the lead contaminated soils in the presence of various levels of road salts (5%, 10%, 20%, 30% and 40%). The results of the leaching test showed that lead leaching dramatically increased as the road salt content increased as a result of the formation of lead-chloride complexes, but different lead leaching patterns were observed in the presence of NaCl- and CaCl 2 -based road salts at a high content of road salts (>20%). Additional leaching tests that include 30% road salts and different soil samples showed a variety of leaching patterns by soil samples. The sequential extraction of each soil sample showed that a high fraction of organic matter bound lead was associated with lead contamination. The higher the fraction of organic matter bound lead contained in soil, the greater the effects of calcium on reducing lead leaching, observations showed. Copyright © 2016 Elsevier B.V. All rights reserved.

‘Norman’ southern highbush blueberry

USDA-ARS?s Scientific Manuscript database

‘Norman’ is the third cultivar released from the University of Arkansas blueberry breeding program, which began in the late 1970s and has involved cooperative efforts with the U.S. Department of Agriculture (USDA). Previous cultivars released from this breeding program were ‘Ozarkblue’ and ‘Summit’....

Design, development and evaluation of driver wellness programs. Technical memorandum 3 : pilot test results and marketing plan

DOT National Transportation Integrated Search

1999-10-31

In May, 1997, the National Private Truck Councils (NPTC) Private Fleet Management Institute (PFMI) began a research program in cooperation with Sue Roberts Health Concepts, Inc., ATA Foundation, Inc., and the Federal Motor Carrier Safety Administr...

Overview of Preserve America

Science.gov Websites

Ground Project, New York; the Corinth and Alcorn County Mississippi Heritage Tourism Initiative heritage tourism programs. Since the program began in 2003, 843 communities have been designated as regional press releases; official notification of designation to state tourism offices and visitors bureaus

Workplace Literacy: The Effects of an In-house Program on the Organization.

ERIC Educational Resources Information Center

Fretz, Barbara

The effects of an in-house workplace literacy program on an organization are examined. A small Canadian manufacturing plant that began a workplace literacy program called Learning in the Workplace in 1990 was the site of this case study research. The plant was CCL Custom Manufacturing, which specialized in household powder-based products. Four…

Beyond the atmosphere: Early years of space science

NASA Technical Reports Server (NTRS)

Newell, H. E.

1980-01-01

From the rocket measurements of the upper atmosphere and Sun that began in 1946, space science gradually emerged as a new field of scientific activity. The course of the United State space program is viewed in an historical context. Major emphasis is on NASA and its programs. The funding, staffing, organization, and priorities of the space program were reviewed.

Patterns and Trends of Canadian Social Work Doctoral Dissertations

ERIC Educational Resources Information Center

Rothwell, David W.; Lach, Lucyana; Blumenthal, Anne; Akesson, Bree

2015-01-01

The first social work doctoral program in Canada began in 1952. Relatively recently, the number of programs has grown rapidly, doubling in the past 10 years to 14 programs. Despite the expansion there is no systematic understanding of the patterns and trends in doctoral research. In this study we review 248 publicly available dissertations from…

Blindness and Computer Networking at iTEC [Information Technology Education Center].

ERIC Educational Resources Information Center

Goins, Shannon

A new program to train blind and visually impaired individuals to design and run a computer network has been developed. The program offers the Microsoft Certified Systems Engineer (MCSE) training. The program, which began in February 2001, recently graduated its first class of students, who are currently completing 1-month internships to complete…

Voices from the Field: "Systems Trump Programs" A Case for Agency Support in Afterschool

ERIC Educational Resources Information Center

Hodgkins, Alexandria

2017-01-01

When Alexandria Hodgkins began her inquiry for the National Institute on Out-of-School Time's Afterschool Matters Practitioner Research Fellowship, she wanted to investigate afterschool programs that had been rated "excellent" by funders. Wanting to understand what excellent programs look like and how they get that way, she writes that…

The Augusta College Humanities Program: Strengthening an Introductory Three-Course Sequence.

ERIC Educational Resources Information Center

American Association of State Colleges and Universities, Washington, DC.

Presented is a compilation of materials concerning the Augusta College Humanities Program in Augusta, Georgia, beginning with a brief description of the program and its background. In 1984, the college began a 2.5-year project to revitalize and strengthen its required sophomore level three course humanities sequence (Greece and Rome, the Middle…

Metro-Minnesota Community Clinical Oncology Program (MM-CCOP) | Division of Cancer Prevention

Cancer.gov

The Metro-Minnesota Community Clinical Oncology (MMCCOP) program has a long-standing history which clearly demonstrates the success of the consortium, as demonstrated by both the ongoing commitment of the original consortium members and the growth of the consortium from 1979 through 2014. The MMCCOP consortium represents an established community program base which began in

Naval Medical Research And Development News. Volume 7, Issue 8

DTIC Science & Technology

2015-08-01

their bionomics, distribution, and taxonomy to have the best tools to carry out our preventive medicine programs.” In fact , the Navy has been employing...areas on Earth , so there are many amazing and interesting discoveries yet to be made.” New Sand Fly Species and Potential Vector of Leishmaniasis...Laboratory’s Center for Bio/Molecular Science and Engineering in Washington, D.C. began a collaboration to re-design amalgam separators. These efforts began

Evaluation of the School Breakfast Program Pilot Project: Findings from the First Year of Implementation. Nutrition Assistance Program Report Series.

ERIC Educational Resources Information Center

McLaughlin, Joan E.; Bernstein, Lawrence S.; Crepinsek, May Kay; Daft, Lynn M.; Murphy, J. Michael

In 1998, Congress authorized implementation of a 3-year pilot breakfast program involving 4,300 students in elementary schools in 6 school districts representing a range of economic and demographic characteristics. The program began in the 2000-01 school year. This lengthy report presents the findings from the pilot's first year. The study had two…

If You Build It, Will They Come? Tales of Developing a New Degree Program in Actuarial Science

ERIC Educational Resources Information Center

Marano, Lisa E.

2014-01-01

In 2007, the B.S. in Applied Mathematics program consisting of five concentrations, including Actuarial Science, began at West Chester University of Pennsylvania, and we graduated our first class (of one) that December. We describe our program, some ideas to consider when planning your own program, and share some of the successes of our program…

Will the Pell Grant Have the Ability To Provide Access and Choice to Low-Income Students in the Future?

ERIC Educational Resources Information Center

Lechuga, Vicente M.

This paper provides a basic understanding of the Pell Grant program and summarizes the evidence regarding its effectiveness. The Basic Educational Opportunities Program, known as the Pell Grant program, began in 1973 as a means of providing disadvantaged students access to a postsecondary education. The Pell Grant program has tried to keep up with…

Water-quality, streamflow, and ancillary data for nutrients in streams and rivers across the nation, 1992-2001

USGS Publications Warehouse

Mueller, David K.; Spahr, Norman E.

2005-01-01

Introduction: This report is the companion data report for: Nutrients in Streams and Rivers Across the Nation - 1992-2001 (D.K. Mueller and N.E. Spahr, U.S. Geological Survey written commun., 2005). The data contained in this report were collected as part of the National Water-Quality Assessment (NAWQA) Program. Investigations were conducted in 51 large river basins and aquifer systems, which are referred to as 'study units.' Implementation of study-unit investigations were phased so that high-intensity sampling occurred in about one-third of the study units at a time. Investigations in the first 20 study units began in 1991, and stream sampling began in 1992; however, most samples were collected during water years 1993-95. (Water year is defined as the period from October through September and is identified by the year in which it ends.) A second group of 16 study-unit investigations began in 1994, with most of the sampling completed during water years 1996-98. A third group, consisting of 15 study units, began in 1997 with most of the data collected during water years 1999-2001. At some sites, additional sampling continued after the high-intensity time period. Gilliom and others (1995) provide additional information about study-unit sampling design. Additional information about the NAWQA program is available at http://water.usgs.gov/nawqa/index.html.

Controlling mechanisms of metals release form cement-based waste form in acetic acid solution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cheng, Kuang Ye.

1991-01-01

The purpose of this dissertation is to identify the individual leaching mechanisms of metals by knowing the pH profile within the leached specimen and the physical and chemical properties of the leached material. Leaching of cement-based waste form in acetic acid solutions with different acidic strengths has been investigated in this work. The pH profile along the acid penetration route in the cement-based waste form was identified by various pH color indicators. The pH in the surface altered layer varies from 5.0 to 6.0, which is very close to the pH in the bulk leachate. A reacting zone, where themore » pH abruptly changes from 6 to 12, sharply divides the altered surface layer from the remaining unleached waste form or kernel. Leaching of metals is controlled by the acidity available in the leachant. Dissolution of alkaline materials leaves a silica-rich layer on the surface of the cement-based waste form. This surface layer exhibits different properties than those of the unleached material. The surface layer has a higher water content, is lighter weight, and is soft and friable. Furthermore, the abundant silicate content on the solid surface detains portion of the leached metals, while they are moving through the leached layer into bulk solution. The leaching of metals is a consequence of acid penetration. The distance from the solid/solution interface to the front of the leaching boundary can be regarded as the depth of leaching zone, where the metals dissolve and diffuse out of the waste form. The metal ions diffuse through the leached layer may be retarded on the solid surface by the pH-dependent adsorption reactions. It is found that the leaching process through the leached layer is diffusion-controlled for calcium and cadmium, whereas diffusion and adsorption occur simultaneously in the leached layer for lead and arsenic.« less

Model-based coefficient method for calculation of N leaching from agricultural fields applied to small catchments and the effects of leaching reducing measures

NASA Astrophysics Data System (ADS)

Kyllmar, K.; Mårtensson, K.; Johnsson, H.

2005-03-01

A method to calculate N leaching from arable fields using model-calculated N leaching coefficients (NLCs) was developed. Using the process-based modelling system SOILNDB, leaching of N was simulated for four leaching regions in southern Sweden with 20-year climate series and a large number of randomised crop sequences based on regional agricultural statistics. To obtain N leaching coefficients, mean values of annual N leaching were calculated for each combination of main crop, following crop and fertilisation regime for each leaching region and soil type. The field-NLC method developed could be useful for following up water quality goals in e.g. small monitoring catchments, since it allows normal leaching from actual crop rotations and fertilisation to be determined regardless of the weather. The method was tested using field data from nine small intensively monitored agricultural catchments. The agreement between calculated field N leaching and measured N transport in catchment stream outlets, 19-47 and 8-38 kg ha -1 yr -1, respectively, was satisfactory in most catchments when contributions from land uses other than arable land and uncertainties in groundwater flows were considered. The possibility of calculating effects of crop combinations (crop and following crop) is of considerable value since changes in crop rotation constitute a large potential for reducing N leaching. When the effect of a number of potential measures to reduce N leaching (i.e. applying manure in spring instead of autumn; postponing ploughing-in of ley and green fallow in autumn; undersowing a catch crop in cereals and oilseeds; and increasing the area of catch crops by substituting winter cereals and winter oilseeds with corresponding spring crops) was calculated for the arable fields in the catchments using field-NLCs, N leaching was reduced by between 34 and 54% for the separate catchments when the best possible effect on the entire potential area was assumed.

Ranking Coal Ash Materials for Their Potential to Leach Arsenic and Selenium: Relative Importance of Ash Chemistry and Site Biogeochemistry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schwartz, Grace E.; Hower, James C.; Phillips, Allison L.

The chemical composition of coal ash is highly heterogeneous and dependent on the origin of the source coal, combustion parameters, and type and configuration of air pollution control devices. This heterogeneity results in uncertainty in the evaluation of leaching potential of contaminants from coal ash. The goal of this work was to identify whether a single leaching protocol could roughly group high-leaching potential coal ash from low-leaching potential coal ash, with respect to arsenic (As) and selenium (Se). We used four different leaching tests, including the Toxicity Characteristic Leaching Protocol (TCLP), natural pH, aerobic sediment microcosms, and anaerobic sediment microcosmsmore » on 10 different coal ash materials, including fly ash, lime-treated ash, and flue gas desulfurization materials. Leaching tests showed promise in categorizing high and low-leaching potential ash materials, indicating that a single point test could act as a first screening measure to identify high-risk ash materials. However, the amount of contaminant leached varied widely across tests, reflecting the importance of ambient conditions (pH, redox state) on leaching. These results demonstrate that on-site geochemical conditions play a critical role in As and Se mobilization from coal ash, underscoring the need to develop a situation-based risk assessment framework for contamination by coal ash pollutants.« less

Use of adjuvants to minimize leaching of herbicides in soil

NASA Astrophysics Data System (ADS)

Alva, Ashok K.; Singh, Megh

1991-03-01

Excessive leaching of herbicides affects their efficacy against target weeds and results in contamination of groundwater. Use of adjuvants that can weakly bind herbicides and in turn release them slowly is a valuable technique to prolong the efficacy of herbicides and to minimize their leaching into groundwater. Effects of activated charcoal, three humic substances (Enersol SP 85%, Enersol 12%, and Agroliz), or a synthetic polymer (Hydrosorb) on the leaching of bromacil, dicamba, and simazine were investigated in leaching columns using a Candler fine sand (Typic Quartzipsamment). The addition of adjuvants had no harmful effects on physical properties of the soil as evident from lack of its affects on water percolation. When no adjuvants were used, 69%, 37%, and 4% of applied dicamba, bromacil, and simazine, respectively, were leached in the first pore volume of leachate (⋍3.2 cm rainfall). With five pore volumes of leachate (⋍16 cm rainfall), bromacil and dicamba were leached completely and only 80% of simazine was leached. Using Enersol 12% adjuvant resulted in a 13%-18% reduction in leaching of dicamba and bromacil in five pore volumes of leachate. The leaching of simazine was significantly decreased when any of the five adjuvants mentioned above were used. However, the decrease in leaching was significantly greater when using Enersol SP 85% or Enersol 12% (24%-28%) than when using the other adjuvants (12%-16%).

Ranking Coal Ash Materials for Their Potential to Leach Arsenic and Selenium: Relative Importance of Ash Chemistry and Site Biogeochemistry

DOE PAGES

Schwartz, Grace E.; Hower, James C.; Phillips, Allison L.; ...

2018-01-23

The chemical composition of coal ash is highly heterogeneous and dependent on the origin of the source coal, combustion parameters, and type and configuration of air pollution control devices. This heterogeneity results in uncertainty in the evaluation of leaching potential of contaminants from coal ash. The goal of this work was to identify whether a single leaching protocol could roughly group high-leaching potential coal ash from low-leaching potential coal ash, with respect to arsenic (As) and selenium (Se). We used four different leaching tests, including the Toxicity Characteristic Leaching Protocol (TCLP), natural pH, aerobic sediment microcosms, and anaerobic sediment microcosmsmore » on 10 different coal ash materials, including fly ash, lime-treated ash, and flue gas desulfurization materials. Leaching tests showed promise in categorizing high and low-leaching potential ash materials, indicating that a single point test could act as a first screening measure to identify high-risk ash materials. However, the amount of contaminant leached varied widely across tests, reflecting the importance of ambient conditions (pH, redox state) on leaching. These results demonstrate that on-site geochemical conditions play a critical role in As and Se mobilization from coal ash, underscoring the need to develop a situation-based risk assessment framework for contamination by coal ash pollutants.« less

PRESERVATIVE LEACHING FROM WEATHERED CCA-TREATED WOOD

EPA Science Inventory

Disposal of discarded CCA-treated wood in landfills raises concerns with respect to leaching of preservative compounds. When unweathered CCA-treated wood is leached using the toxicity characteristic leaching procedure (TCLP), arsenic concentrations exceed the toxicity characteris...

Kinetic and Mechanism Study of Vanadium Acid Leaching from Black Shale Using Microwave Heating Method

NASA Astrophysics Data System (ADS)

Wang, Jing-peng; Zhang, Yi-min; Huang, Jing; Liu, Tao

2018-04-01

The leaching kinetics of the vanadium leaching process were investigated by the comparison of microwave heating and conventional heating methods. Microwave heating with CaF2 had a synergistic effect and improved the vanadium leaching efficiency. In contrast to conventional heating leaching, microwave heating accelerated the vanadium leaching rate by approximately 1-3% and by approximately 15% when CaF2 was also used. The kinetics analysis showed that the calculated activation energy decreased in the microwave heating method in the presence and absence of CaF2. The control procedure of leaching also changed from a chemical reaction control step to a mixed chemical diffusion control step upon the addition of CaF2. Microwave heating was shown to be suitable for leaching systems with diffusion or mixed chemical diffusion control steps when the target mineral does not have a microwave absorbing ability.

Kinetic and Mechanism Study of Vanadium Acid Leaching from Black Shale Using Microwave Heating Method

NASA Astrophysics Data System (ADS)

Wang, Jing-peng; Zhang, Yi-min; Huang, Jing; Liu, Tao

2018-06-01

The leaching kinetics of the vanadium leaching process were investigated by the comparison of microwave heating and conventional heating methods. Microwave heating with CaF2 had a synergistic effect and improved the vanadium leaching efficiency. In contrast to conventional heating leaching, microwave heating accelerated the vanadium leaching rate by approximately 1-3% and by approximately 15% when CaF2 was also used. The kinetics analysis showed that the calculated activation energy decreased in the microwave heating method in the presence and absence of CaF2. The control procedure of leaching also changed from a chemical reaction control step to a mixed chemical diffusion control step upon the addition of CaF2. Microwave heating was shown to be suitable for leaching systems with diffusion or mixed chemical diffusion control steps when the target mineral does not have a microwave absorbing ability.

Cementitious Barriers Partnership - FY2015 End-Year Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burns, H. H.; Flach, G. P.; Langton, C. A.

2015-09-17

The DOE-EM Office of Tank Waste Management Cementitious Barriers Partnership (CBP) is chartered with providing the technical basis for implementing cement-based waste forms and radioactive waste containment structures for long-term disposal. Therefore, the CBP ultimate purpose is to support progress in final treatment and disposal of legacy waste and closure of High-Level Waste (HLW) tanks in the DOE complex. This status report highlights the CBP 2015 Software and Experimental Program efforts and accomplishments that support DOE needs in environmental cleanup and waste disposal. DOE needs in this area include: Long-term performance predictions to provide credibility (i.e., a defensible technical basis)more » for regulator and DOE review and approvals, Facility flow sheet development/enhancements, and Conceptual designs for new disposal facilities. In 2015, the CBP developed a beta release of the CBP Software Toolbox – “Version 3.0”, which includes new STADIUM carbonation and damage models, a new SRNL module for estimating hydraulic properties and flow in fractured and intact cementitious materials, and a new LeachXS/ORCHESTRA (LXO) oxidation module. In addition, the STADIUM sulfate attack and chloride models have been improved as well as the LXO modules for sulfate attack, carbonation, constituent leaching, and percolation with radial diffusion (for leaching and transport in cracked cementitious materials). These STADIUM and LXO models are applicable to and can be used by both DOE and the Nuclear Regulatory Commission (NRC) end-users for service life prediction and long-term leaching evaluations of radioactive waste containment structures across the DOE complex.« less

Process development for recovery of copper and precious metals from waste printed circuit boards with emphasize on palladium and gold leaching and precipitation.

PubMed

Behnamfard, Ali; Salarirad, Mohammad Mehdi; Veglio, Francesco

2013-11-01

A novel hydrometallurgical process was proposed for selective recovery of Cu, Ag, Au and Pd from waste printed circuit boards (PCBs). More than 99% of copper content was dissolved by using two consecutive sulfuric acid leaching steps in the presence of H2O2 as oxidizing agents. The solid residue of 2nd leaching step was treated by acidic thiourea in the presence of ferric iron as oxidizing agent and 85.76% Au and 71.36% Ag dissolution was achieved. The precipitation of Au and Ag from acidic thiourea leachate was investigated by using different amounts of sodium borohydride (SBH) as a reducing agent. The leaching of Pd and remained gold from the solid reside of 3rd leaching step was performed in NaClO-HCl-H2O2 leaching system and the effect of different parameters was investigated. The leaching of Pd and specially Au increased by increasing the NaClO concentration up to 10V% and any further increasing the NaClO concentration has a negligible effect. The leaching of Pd and Au increased by increasing the HCl concentration from 2.5 to 5M. The leaching of Pd and Au were endothermic and raising the temperature had a positive effect on leaching efficiency. The kinetics of Pd leaching was quite fast and after 30min complete leaching of Pd was achieved, while the leaching of Au need a longer contact time. The best conditions for leaching of Pd and Au in NaClO-HCl-H2O2 leaching system were determined to be 5M HCl, 1V% H2O2, 10V% NaClO at 336K for 3h with a solid/liquid ratio of 1/10. 100% of Pd and Au of what was in the chloride leachate were precipitated by using 2g/L SBH. Finally, a process flow sheet for the recovery of Cu, Ag, Au and Pd from PCB was proposed. Copyright © 2013 Elsevier Ltd. All rights reserved.

St. Louis airport site annual environmental report for calendar year 1990, St. Louis, Missouri

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1991-08-01

Environmental monitoring of the US Department of Energy's (DOE) St. Louis Airport Site (SLAPS) and surrounding area began in 1984. SLAPS is part of the Formerly Utilized Sites Remedial Action Program (FUSRAP), a DOE program to decontaminate or otherwise control sites where residual radioactive materials remain from the early years of the nation's atomic energy program or from commercial operations causing conditions that Congress has authorized DOE to remedy. Monitoring results are compared with applicable Environmental Protection Agency (EPA) standards; federal, state, and local applicable or relevant and appropriate requirements (ARARs); and/or DOE derived concentration guidelines (DCGs). Environmental standards, ARARs,more » and DCGs are established to protect public health and the environment. Results from the 1990 environmental monitoring program demonstrated that the concentrations of contaminants of concern were all below applicable standards, ARARs, and guidelines. Site activities in 1990 were limited to maintenance. SLAPS was in compliance with all applicable regulations during 1990 and has remained in compliance since 1984, when the environmental monitoring program and remedial action began.« less

STRUCTURE-ACTIVITY RELATIONSHIP AMONG ORGANOTINS IN AN IN VITRO MODEL OF NEURONAL DIFFERENTIATION AND PROGRAMMED CELL DEATH.

EPA Science Inventory

The organotins are used as heat stabilizers in PVC pipes and as marine biocides. Human exposure to monomethyltin (MMT) and dimethyltin (DMT) can occur in the water supply as a result of leaching from PVC pipes. Developmental exposure of rats to MMT and the known neurotoxicant t...

SUPERFUND INNOVATIVE TECHNOLOGY EVALUATION PROGRAM Evaluation of Soil Amendment Technologies at the Crooksville/RosevillePottery Area of Concern Rocky Mountain Remediation ServicesEnvirobond™ Process

EPA Science Inventory

RMRS developed the Envirobond™ process to treat heavy metals in soil.This phosphate-based technology consists of a proprietary powder and solution that binds with metals in contaminated waste. RMRS claims that the Envirobond™ process converts metal contaminants from their leach...

Leaching of natural colloids from forest topsoils and their relevance for phosphorus mobility.

PubMed

Missong, Anna; Holzmann, Stefan; Bol, Roland; Nischwitz, Volker; Puhlmann, Heike; V Wilpert, Klaus; Siemens, Jan; Klumpp, Erwin

2018-09-01

The leaching of P from the upper 20cm of forest topsoils influences nutrient (re-)cycling and the redistribution of available phosphate and organic P forms. However, the effective leaching of colloids and associated P forms from forest topsoils was so far sparsely investigated. We demonstrated through irrigation experiments with undisturbed mesocosm soil columns, that significant proportions of P leached from acidic forest topsoils were associated with natural colloids. These colloids had a maximum size of 400nm. By means of Field-flow fractionation the leached soil colloids could be separated into three size fractions. The size and composition was comparable to colloids present in acidic forest streams known from literature. The composition of leached colloids of the three size classes was dominated by organic carbon. Furthermore, these colloids contained large concentrations of P which amounted between 12 and 91% of the totally leached P depending on the type of the forest soil. The fraction of other elements leached with colloids ranged between 1% and 25% (Fe: 1-25%; C org : 3-17%; Al: <4%; Si, Ca, Mn: all <2%). The proportion of colloid-associated P decreased with increasing total P leaching. Leaching of total and colloid-associated P from the forest surface soil did not increase with increasing bulk soil P concentrations and were also not related to tree species. The present study highlighted that colloid-facilitated P leaching can be of higher relevance for the P leaching from forest surface soils than dissolved P and should not be neglected in soil water flux studies. Copyright © 2018 Elsevier B.V. All rights reserved.

Recycling process for recovery of gallium from GaN an e-waste of LED industry through ball milling, annealing and leaching.

PubMed

Swain, Basudev; Mishra, Chinmayee; Kang, Leeseung; Park, Kyung-Soo; Lee, Chan Gi; Hong, Hyun Seon

2015-04-01

Waste dust generated during manufacturing of LED contains significant amounts of gallium and indium, needs suitable treatment and can be an important resource for recovery. The LED industry waste dust contains primarily gallium as GaN. Leaching followed by purification technology is the green and clean technology. To develop treatment and recycling technology of these GaN bearing e-waste, leaching is the primary stage. In our current investigation possible process for treatment and quantitative leaching of gallium and indium from the GaN bearing e-waste or waste of LED industry dust has been developed. To recycle the waste and quantitative leaching of gallium, two different process flow sheets have been proposed. In one, process first the GaN of the waste the LED industry dust was leached at the optimum condition. Subsequently, the leach residue was mixed with Na2CO3, ball milled followed by annealing, again leached to recover gallium. In the second process, the waste LED industry dust was mixed with Na2CO3, after ball milling and annealing, followed acidic leaching. Without pretreatment, the gallium leaching was only 4.91 w/w % using 4M HCl, 100°C and pulp density of 20g/L. After mechano-chemical processing, both these processes achieved 73.68 w/w % of gallium leaching at their optimum condition. The developed process can treat and recycle any e-waste containing GaN through ball milling, annealing and leaching. Copyright © 2015 Elsevier Inc. All rights reserved.

Acid extraction of molybdenum, nickel and cobalt from mineral sludge generated by rainfall water at a metal recycling plant.

PubMed

Vemic, M; Bordas, F; Guibaud, G; Comte, S; Joussein, E; Lens, P N L; Van Hullebusch, E D

2016-01-01

This study investigated the leaching yields of Mo, Ni and Co from a mineral sludge of a metal recycling plant generated by rainfalls. The investigated mineral sludge had a complex heterogeneous composition, consisting of particles of settled soil combined with metal-bearing particles (produced by catalysts, metallic oxides and battery recycling). The leaching potential of different leaching reagents (stand-alone strong acids (HNO3 (68%), H2SO4 (98%) and HCl (36%)) and acid mixtures (aqua regia (nitric + hydrochloric (1:3)), nitric + sulphuric (1:1) and nitric + sulphuric + hydrochloric (2:1:1)) was investigated at changing operational parameters (solid-liquid (S/L) ratio, leaching time and temperature), in order to select the leaching reagent which achieves the highest metal leaching yields. Sulphuric acid (98% H2SO4) was found to be the leachant with the highest metal leaching potential. The optimal leaching conditions were a three-stage successive leaching at 80 °C with a leaching time of 2 h and S/L ratio of 0.25 g L(-1). Under these conditions, the achieved mineral sludge sample leaching yields were 85.5%, 40.5% and 93.8% for Mo, Ni and Co, respectively. The higher metal leaching potential of H2SO4 in comparison with the other strong acids/acid mixtures is attributed to the fact that H2SO4 is a diacidic compound, thus it has more H(+) ions, resulting in its stronger oxidizing power and corrosiveness.

Assessing Metal Mobilization from Industrially Lead-Contaminated Soils Located at an Urban Site

EPA Science Inventory

A series of leaching and partitioning tests (Toxicity Characteristic Leaching Procedure (TCLP), Synthetic Precipitation Leaching Procedure (SPLP), Controlled Acidity Leaching Protocol (CALP), Acid Neutralization Capacity (ANC), and sequential extraction) were applied to three dif...

Investigation on microwave heating for direct leaching of chalcopyrite ores and concentrates

NASA Astrophysics Data System (ADS)

Onol, Kubra; Saridede, Muhlis Nezihi

2013-03-01

The use of microwave energy in materials processing is a relatively new development presenting numerous advantages because of the rapid heating feature. Microwave technology has great potential to improve the extraction efficiency of metals in terms of both a reduction in required leaching time and an increase in the recovery of valuable metals. This method is especially pertinent in view of the increased demand for environment-friendly processes. In the present study, the influence of microwave heating on the direct leaching of chalcopyrite ores and concentrates were investigated. The results of microwave leaching experiments were compared with those obtained under conventional conditions. During these processes, parameters such as leaching media, temperature, and time have been worked to determine the optimum conditions for proper copper dissolution. Experimental results show that microwave leaching is more efficient than conventional leaching. The optimum leaching conditions for microwave leaching are the solid-to-liquid ratio of 1:100 g/mL, the temperature of 140°C, the solution of 0.5 M H2SO4 + 0.05 M Fe2(SO4)3, and the time of 1 h.

Ionic liquids for metal extraction from chalcopyrite: solid, liquid and gas phase studies.

PubMed

Kuzmina, O; Symianakis, E; Godfrey, D; Albrecht, T; Welton, T

2017-08-16

We studied leaching of Cu and Fe from naturally occurring chalcopyrite ore using aqueous solutions of ionic liquids (ILs) based on imidazolium and ethylammonium cations and hydrogensulfate, nitrate, acetate or dicyanamide anions. Liquid, solid and gas phases of the leaching systems were characterised. We have shown that nonoxidative leaching is greatly dependant not only on temperature and pH, but on the anion species of the IL. Solutions of 1-butylimidazolium hydrogen sulfate exhibited the best leaching performance among hydrogen sulphate ILs. We have suggested that the formation of an oxide layer in some ILs may be responsible for a reduced leaching ability. The analysis of the gas phase showed the production of CO 2 and CS 2 in all leached samples. Our results suggested that the CS 2 produced upon leaching could be responsible for decreasing the sulfur, but not oxide, layer on the surface of chalcopyrite samples and therefore more efficient leaching. This is the first study, to our knowledge, to provide a systematic comparison of the leaching performance of ILs composed of different anions and cations and without added oxidants.

Quantification of the effects of environmental leaching factors on emissions from bottom ash in road construction.

PubMed

Ecke, Holger; Aberg, Annika

2006-06-01

The re-use of bottom ash in road construction necessitates a tool to predict the impact of trace metals on the surroundings over the lifetime of the road. The aim of this work was to quantify the effect of environmental factors that are supposed to influence leaching, so as to suggest guidelines in developing a leaching procedure for the testing of incineration residues re-used in road constructions. The effects of pH, L/S (liquid-to-solid ratio), leaching time, and leaching atmosphere on the leachate concentrations of Cd, Cr, Cu, Ni, Pb, and Zn were studied using a two-level full factorial design. The most significant factor for all responses was the pH, followed by L/S, though the importance of pH and L/S is often ignored in leaching tests. Multiple linear regression models describing the variation in leaching data had R(2) values ranging from 61-97%. A two-step pH-stat leaching procedure that considers pH as well as L/S and leaching time was suggested.

CALIFORNIA'S FIRST AERATION PLANTS FOR CORROSION CONTROL

EPA Science Inventory

As required by the Lead and Copper Rule (LCR), Idyllwild Water District (IWD) and Pine Cove Water District (PCWD) conducted a sampling and testing program in 1993-1994. The program began with an evaluation of local household plumbing to identify 20 sites in each District which wo...

Evaluation of state ignition interlock programs : interlock use analyses from 28 states, 2006–2011.

DOT National Transportation Integrated Search

2015-05-01

In 2010, the Centers for Disease Control and Prevention (CDC) and NHTSA began collaborating on a project to evaluate ignition interlock programs in selected States. The purpose of the evaluation was to provide information and best practices to States...

Kentucky's Automotive Certification Program.

ERIC Educational Resources Information Center

Kentucky State Dept. of Education, Frankfort. Office of Vocational Education.

The state of Kentucky recognized a need to standardize automotive mechanics training throughout the state and to establish minimum guidelines for the quality of instruction in such programs. To meet these needs, the Office of Vocational Education selected the National Institute for Automotive Service Excellence (ASE) and began the certification…

Diversifying the STEM Pipeline: The Model Replication Institutions Program

ERIC Educational Resources Information Center

Cullinane, Jenna

2009-01-01

In 2006, the National Science Foundation (NSF) began funding the Model Replication Institutions (MRI) program, which sought to improve the quality, availability, and diversity of science, technology, engineering, and mathematics (STEM) education. Faced with pressing national priorities in the STEM fields and chronic gaps in postsecondary…

Contamination of groundwater by outdoor highway deicing agent storage

NASA Astrophysics Data System (ADS)

Ostendorf, David W.; Hinlein, Erich S.; Rotaru, Camelia; DeGroot, Don J.

2006-07-01

This research quantifies the impact of outdoor highway deicing agent storage on groundwater quality. Data and theory realize the objective at a well characterized salt/premix storage facility on a glacial drumlin comprised of clayey sand till. Tritium and tritiogenic helium were observed in 17 monitoring wells in 2003, while chloride concentrations were measured in 43 monitoring wells from 1998 through 2004. The 3He/ 3H ratios confirm an analytical model of drumlin hydraulics (Ostendorf, D.W., DeGroot, D.J., Shelburne, W.M., and Mitchell, T.J., 2004. Hydraulic head in a clayey sand till over multiple timescales. Can. Geotech. J. 41, 89-105.), and support advective travel time estimates from the monitoring well screens back to the water table. An advective balance of recharge, precipitation, and surface runoff routes the water table Cl - concentrations inwards to the outdoor storage pile maintained at the site from the 1960s to the mid 1980s. Concentrations as high as 320 meq Cl -/L were observed in groundwater, although the deicing agent contamination had not yet reached the bottom of the drumlin in the study area. The travel time simulations yield a 200 meq Cl -/L water table isopleth in 1985 under the prior outdoor storage pile. The recharge concentration model matches the radial decrease of Cl - water table concentrations from the pile, and implies that 4400 kg of Cl - leached into the groundwater in 1985. This is about 0.3% of the deicing agent Cl - stored at the site each year. These results suggest that outdoor storage of highway deicing agents significantly impacted groundwater quality near the pile. The groundwater quality began to recover after source removal however: the leached Cl - flux dropped to 2,300 kg in 1992, more than 5 years after elimination of the outdoor storage pile.

Characterizing the Leaching Behavior of Coal Combustion Residues using the Leaching Environmental Assessment Framework (LEAF) to Inform Future Management Decisions

EPA Science Inventory

Abstract for presentation on Characterizing the Leaching Behavior of Coal Combustion Residues using the Leaching Environmental Assessment Framework (LEAF) to Inform Future Management Decisions. The abstract is attached.

Small-scale and large-scale testing of photo-electrochemically activated leaching technology in Aprelkovo and Delmachik Mines

NASA Astrophysics Data System (ADS)

Sekisov, AG; Lavrov, AYu; Rubtsov, YuI

2017-02-01

The paper gives a description of tests and trials of the technology of heap gold leaching from rebellious ore in Aprelkovo and Delmachik Mines. Efficiency of leaching flowsheets with the stage-wise use of activated solutions of different reagents, including active forms of oxygen, is evaluated. Carbonate-peroxide solutions are used at the first stage of leaching to oxidize sulfide and sulfide-arsenide ore minerals to recover iron and copper from them. The second stage leaching uses active cyanide solutions to leach encapsulated and disperse gold and silver.

Effect of temperature on iron leaching from bauxite residue by sulfuric acid.

PubMed

Liu, Zhi-Rong; Zeng, Kai; Zhao, Wei; Li, Ying

2009-01-01

Bauxite residue, as solid waste from alumina production, contains mainly hematite [Fe2O3]. Kinetic study of iron leaching of bauxite residue by diluted sulfuric acid at atmospheric pressure has been investigated. The results have been obtained as following: (i) Temperature play an important role in iron leaching from bauxite residue. Higher temperature is favor of Fe(III) leaching from bauxite residue. (ii) The leaching process is applicable to the intra-particle diffusion model and the apparent activation energy of model of leaching is found to be 17.32 kJ/mol.

Detoxification of mercury pollutant leached from spent fluorescent lamps using bacterial strains.

PubMed

Al-Ghouti, Mohammad A; Abuqaoud, Reem H; Abu-Dieyeh, Mohammed H

2016-03-01

The spent fluorescent lamps (SFLs) are being classified as a hazardous waste due to having mercury as one of its main components. Mercury is considered the second most toxic heavy metal (arsenic is the first) with harmful effects on animal nervous system as it causes different neurological disorders. In this research, the mercury from phosphor powder was leached, then bioremediated using bacterial strains isolated from Qatari environment. Leaching of mercury was carried out with nitric and hydrochloric acid solutions using two approaches: leaching at ambient conditions and microwave-assisted leaching. The results obtained from this research showed that microwave-assisted leaching method was significantly better in leaching mercury than the acid leaching where the mercury leaching efficiency reached 76.4%. For mercury bio-uptake, twenty bacterial strains (previously isolated and purified from petroleum oil contaminated soils) were sub-cultured on Luria Bertani (LB) plates with mercury chloride to check the bacterial tolerance to mercury. Seven of these twenty strains showed a degree of tolerance to mercury. The bio-uptake capacities of the promising strains were investigated using the mercury leached from the fluorescent lamps. Three of the strains (Enterobacter helveticus, Citrobacter amalonaticus, and Cronobacter muytjensii) showed bio-uptake efficiency ranged from 28.8% to 63.6%. Copyright © 2015 Elsevier Ltd. All rights reserved.

Application of hydrometallurgy techniques in quartz processing and purification: a review

NASA Astrophysics Data System (ADS)

Lin, Min; Lei, Shaomin; Pei, Zhenyu; Liu, Yuanyuan; Xia, Zhangjie; Xie, Feixiang

2018-04-01

Although there have been numerous studies on separation and purification of metallic minerals by hydrometallurgy techniques, applications of the chemical techniques in separation and purification of non-metallic minerals are rarely reported. This paper reviews disparate areas of study into processing and purification of quartz (typical non-metallic ore) in an attempt to summarize current work, as well as to suggest potential for future consolidation in the field. The review encompasses chemical techniques of the quartz processing including situations, progresses, leaching mechanism, scopes of application, advantages and drawbacks of micro-bioleaching, high temperature leaching, high temperature pressure leaching and catalyzed high temperature pressure leaching. Traditional leaching techniques including micro-bioleaching and high temperature leaching are unequal to demand of modern glass industry for quality of quartz concentrate because the quartz products has to be further processed. High temperature pressure leaching and catalyzed high temperature pressure leaching provide new ways to produce high-grade quartz sand with only one process and lower acid consumption. Furthermore, the catalyzed high temperature pressure leaching realizes effective purification of quartz with extremely low acid consumption (no using HF or any fluoride). It is proposed that, by integrating the different chemical processes of quartz processing and expounding leaching mechanisms and scopes of application, the research field as a monopolized industry would benefit.

Speciation analysis and leaching behaviors of selected trace elements in spent SCR catalyst.

PubMed

Dai, Zejun; Wang, Lele; Tang, Hao; Sun, Zhijun; Liu, Wei; Sun, Yi; Su, Sheng; Hu, Song; Wang, Yi; Xu, Kai; Liu, Liang; Ling, Peng; Xiang, Jun

2018-09-01

This study investigated heavy metal chemical speciation and leaching behavior from a board-type spent selective catalytic reduction (SCR) catalyst containing high concentrations of vanadium, chromium, nickel, copper, zinc, and lead. A three-step sequential extraction method, standard toxicity characteristic leaching procedure (TCLP), and leaching characteristic tests have been performed. It was found that the mobility of six heavy metals in the spent SCR catalyst was significantly different. The mobility of the six heavy metals exhibited the following order: Ni > Zn > V > Cr > As > Cu. Meanwhile, TCLP test results revealed relatively high Zn and Cr leaching rate of 83.20% and 10.35%, respectively. It was found that leaching rate was positively correlated with available contents (sum of acid soluble, reducible and oxidizable fractions). Leaching characteristics tests indicated that pH substantially affected the leaching of these heavy metals. In particular, the leaching of Cr, Ni, Cu, and Zn was positively influenced by strong acid, while V and As were easily released in the presence of strong acid and strong alkali (pH < 3 or pH > 11). In terms of kinetics, the leaching of Cr, Ni, Cu, Zn, and As within the spent catalyst was dominated by erosion and dissolution processes, which were rapid reaction processes. V was released in large amounts within 1 h, but its leaching amount sharply decreased with time due to readsorption. Copyright © 2018 Elsevier Ltd. All rights reserved.

Long-term environmental impacts of building composites containing waste materials: Evaluation of the leaching protocols.

PubMed

Drinčić, Ana; Nikolić, Irena; Zuliani, Tea; Milačič, Radmila; Ščančar, Janez

2017-01-01

The NEN 7375 test has been proposed for evaluating the long-term environmental impacts caused by the release of contaminants from monolithic building and waste materials. Over a period of 64days, at specific points in time, the leaching solution (demineralised water) is replenished. By applying the NEN 7375 test, leaching of contaminants that is based mainly on diffusion is followed. In the present work, the results from modified leaching protocols were evaluated against those obtained by NEN 7375 test. In modified protocols, synthetic sea, surface and MilliQ water were used for the leaching of selected elements and chromate, molybdate and vanadate from compact and ground building composites (98% mixture of fly ash (80%) and cement (20%), and 2% of electric arc furnace (EAF) dust) over 6months. The leaching solutions were not replenished, imitating both the diffusion and the dissolution of contaminants. The data revealed larger extent of leaching when the leaching solution was not replenished. More extensive was also leaching from ground composites, which simulated the disintegration of the material over time. The composition of the leaching solution influenced the release of the matrix constituents from the composites and, consequently, the amount of elements and their chemical species. Synthetic sea and surface water used as leaching solutions, without replenishing, were found to be suitable to simulate the conditions when the building material is immersed in stagnant environmental waters. Copyright © 2016 Elsevier Ltd. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weber, Paula D.; Flores, Karen A.; Lord, David L.

Bryan Mound 5 ( BM5 ) and West Hackberry 9 ( WH9 ) have the potential to create a significant amount of new storage space should the caverns be deemed "leach - ready". This study discusses the original drilling history of the caverns, surrounding geology, current stability, and, based on this culmination of data, makes a preliminary assessment of the leach potential for the cavern. The risks associated with leaching BM5 present substantial problems for the SPR . The odd shape and large amount of insoluble material make it difficult to de termine whether a targeted leach would have themore » desired effect and create useable ullage or further distort the shape with preferential leaching . T he likelihood of salt falls and damaged or severed casing string is significant . In addition, a targeted le ach would require the relocation of approximately 27 MMB of oil . Due to the abundance of unknown factors associated with this cavern, a targeted leach of BM5 is not recommended. A targeted leaching of the neck of WH 9 could potentially eliminate or diminis h the mid - cavern ledge result ing in a more stable cavern with a more favorable shape. A better understanding of the composition of the surrounding salt and a less complicated leaching history yields more confidence in the ability to successfully leach this region. A targeted leach of WH9 can be recommended upon the completion of a full leach plan with consideration of the impacts upon nearby caverns .« less

Implementation of the Leaching Environmental Assessment Framework

EPA Science Inventory

New leaching tests are available in the U.S. for developing more accurate source terms for use in fate and transport models. For beneficial use or disposal, the use of the leaching environmental assessment framework (LEAF) will provide leaching results that reflect field condit...

A New Generation of Leaching Tests – The Leaching Environmental Assessment Framework

EPA Science Inventory

Provides an overview of newly released leaching tests that provide a more accurate source term when estimating environmental release of metals and other constituents of potential concern (COPCs). The Leaching Environmental Assessment Framework (LEAF) methods have been (1) develo...

40 CFR 411.20 - Applicability; description of the leaching subcategory.

Code of Federal Regulations, 2013 CFR

2013-07-01

... leaching subcategory. 411.20 Section 411.20 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS CEMENT MANUFACTURING POINT SOURCE CATEGORY Leaching Subcategory § 411.20 Applicability; description of the leaching subcategory. The provisions of this subpart are...

40 CFR 411.20 - Applicability; description of the leaching subcategory.

Code of Federal Regulations, 2012 CFR

2012-07-01

... leaching subcategory. 411.20 Section 411.20 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS CEMENT MANUFACTURING POINT SOURCE CATEGORY Leaching Subcategory § 411.20 Applicability; description of the leaching subcategory. The provisions of this subpart are...

40 CFR 411.20 - Applicability; description of the leaching subcategory.

Code of Federal Regulations, 2014 CFR

2014-07-01

... leaching subcategory. 411.20 Section 411.20 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS CEMENT MANUFACTURING POINT SOURCE CATEGORY Leaching Subcategory § 411.20 Applicability; description of the leaching subcategory. The provisions of this subpart are...

40 CFR 411.20 - Applicability; description of the leaching subcategory.

Code of Federal Regulations, 2011 CFR

2011-07-01

... leaching subcategory. 411.20 Section 411.20 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS CEMENT MANUFACTURING POINT SOURCE CATEGORY Leaching Subcategory § 411.20 Applicability; description of the leaching subcategory. The provisions of this subpart are...

Building Their Futures: How Early Head Start Programs Are Enhancing the Lives of Infants and Toddlers in Low-Income Families. Volume I: Technical Report.

ERIC Educational Resources Information Center

Love, John M.; Kisker, Ellen Eliason; Ross, Christine M.; Schochet, Peter Z.; Brooks-Gunn, Jeanne; Boller, Kimberly; Paulsell, Diane; Fuligni, Allison Sidle; Berlin, Lisa J.

Early Head Start began with 68 programs in 1995 and today, almost 650 programs serve some 55,000 low-income families with infants and toddlers. This two-generation program provides high-quality child and family development services, a focus on staff development, and a commitment to community partnerships. A rigorous national evaluation, including…

Shriners Hospitals for Children, Honolulu's experience with telemedicine: program implementation, maintenance, growth, and lessons learned.

PubMed

Ono, Craig M; Lindsey, Jana L

2004-10-01

Shriners Hospitals for Children, Honolulu Telemedicine Program conducts real-time video consultations with remotes sites in Hawaii, Guam, Saipan, American Samoa, the Federated States of Micronesia, and the Republic of the Marshall Islands. The program began in 1999 and has provided over 240 consultations. This report is a summary of the Shriners Hospitals experience and lessons learned regarding program implementation and maintenance.

Extraction of nickel from Ramu laterite by sulphation roasting-water leaching

NASA Astrophysics Data System (ADS)

Wang, Weiwei; Du, Shangchao; Liu, Guo; Tang, Jianwen; Lu, Yeda; Lv, Dong

2017-08-01

Recovery of nickel from a PNG nickel laterite with high content of iron by a sulphation roasting-water leaching has been studied. The influences of sulfuric acid/ore ratio, temperature of roasting and water on recovery efficiency were investigated. The effective separation of nickel over the co-existed elements including iron was achieved by the process with mixing, curing, roasting and leaching stages. Near 100% of nickel was leached from the roasted laterite by water at 80°C in an atmospheric air, while co-leaching of about 2% of iron, under the optimal pre-treatment conditions with the ratio of acid: ore around 0.45:1 and the roasting temperature about 650°C. The advantages and disadvantages of sulphation atmospheric leaching are compared with pressure acid leaching with engineering consideration.

Effects of a Comprehensive Police Suicide Prevention Program

PubMed Central

Mishara, Brian L.; Martin, Normand

2012-01-01

Background: Police suicides are an important problem, and many police forces have high rates. Montreal police suicide rates were slightly higher than other Quebec police rates in the 11 years before the program began (30.5/100,000 per year vs. 26.0/100,000). Aims: To evaluate Together for Life, a suicide prevention program for the Montreal police. Methods: All 4,178 members of the Montreal police participated. The program involved training for all officers, supervisors, and union representatives as well as establishing a volunteer helpline and a publicity campaign. Outcome measures included suicide rates, pre-post assessments of learning, focus groups, interviews, and follow-up of supervisors. Results: In the 12 years since the program began the suicide rate decreased by 79% (6.4/100,000), while other Quebec police rates had a nonsignificant (11%) increase (29.0/100,000). Also, knowledge increased, supervisors engaged in effective interventions, and the activities were highly appreciated. Limitations: Possibly some unidentified factors unrelated to the program could have influenced the observed changes. Conclusions: The decrease in suicides appears to be related to this program since suicide rates for comparable populations did not decrease and there were no major changes in functioning, training, or recruitment to explain the differences. Comprehensive suicide prevention programs tailored to the work environment may significantly impact suicide rates. PMID:22450038

Surfactant-Modified Soil Amendments Reduce Nitrogen and Phosphorus Leaching in a Sand-Based Rootzone.

PubMed

Shaddox, Travis W; Kruse, Jason K; Miller, Grady L; Nkedi-Kizza, Peter; Sartain, Jerry B

2016-09-01

United States Golf Association putting greens are susceptible to nitrogen (N) and phosphorus (P) leaching. Inorganic soil amendments are used to increase moisture and nutrient retention and may influence N and P leaching. This study was conducted to determine whether N and P leaching could be reduced using soil amendments and surfactant-modified soil amendments. Treatments included a control (sand), sand-peat, zeolite, calcined clay, hexadecyltrimethylammonium-zeolite, and hexadecyltrimethylammonium-calcined clay. Lysimeters were filled with a 30-cm rootzone layer of sand-peat (85:15 by volume), below which a 5-cm treatment layer of amendments was placed. A solution of NO-N, NH-N, and orthophosphate-P (2300, 2480, and 4400 μg mL, respectively) was injected at the top of each lysimeter, and leachate was collected using an autocollector set to collect a 10-mL sample every min until four pore volumes were collected. Uncoated amendments, sand, and peat had no influence on NO-N retention, whereas hexadecyltrimethylammonium-coated amendments reduced NO-N leaching to below detectable limits. Both coated and uncoated amendments reduced NH-N leaching, with zeolite reducing NH-N leached to near zero regardless of hexadecyltrimethylammonium coating. Pure sand resulted in a 13% reduction of applied orthophosphate-P leaching, whereas peat contributed to orthophosphate-P leaching. Surfactant-modified amendments reduced orthophosphate-P leaching by as much as 97%. Surfactant-modified soil amendments can reduce NO-N, NH-N, and orthophosphate-P leaching and, thus, may be a viable option for removing leached N and P before they enter surface or ground waters. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Leaching behavior of copper from waste printed circuit boards with Brønsted acidic ionic liquid

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huang, Jinxiu; Chen, Mengjun, E-mail: kyling@swust.edu.cn; Chen, Haiyan

2014-02-15

Highlights: • A Brønsted acidic ILs was used to leach Cu from WPCBs for the first time. • The particle size of WPCBs has significant influence on Cu leaching rate. • Cu leaching rate was higher than 99% under the optimum leaching conditions. • The leaching process can be modeled with shrinking core model, and the E{sub a} was 25.36 kJ/mol. - Abstract: In this work, a Brønsted acidic ionic liquid, 1-butyl-3-methyl-imidazolium hydrogen sulfate ([bmim]HSO{sub 4}), was used to leach copper from waste printed circuit boards (WPCBs, mounted with electronic components) for the first time, and the leaching behavior ofmore » copper was discussed in detail. The results showed that after the pre-treatment, the metal distributions were different with the particle size: Cu, Zn and Al increased with the increasing particle size; while Ni, Sn and Pb were in the contrary. And the particle size has significant influence on copper leaching rate. Copper leaching rate was higher than 99%, almost 100%, when 1 g WPCBs powder was leached under the optimum conditions: particle size of 0.1–0.25 mm, 25 mL 80% (v/v) ionic liquid, 10 mL 30% hydrogen peroxide, solid/liquid ratio of 1/25, 70 °C and 2 h. Copper leaching by [bmim]HSO{sub 4} can be modeled with the shrinking core model, controlled by diffusion through a solid product layer, and the kinetic apparent activation energy has been calculated to be 25.36 kJ/mol.« less

[Leaching Remediation of Copper and Lead Contaminated Lou Soil by Saponin Under Different Conditions].

PubMed

Deng, Hong-xia; Yang, Ya-li; Li, Zhen; Xu, Yan; Li, Rong-hua; Meng, Zhao-fu; Yang, Ya-ti

2015-04-01

In order to investigate the leaching remediation effect of the eco-friendly biosurfactant saponin for Cu and Pb in contaminated Lou soil, batch tests method was used to study the leaching effect of saponin solution on single Cu, Pb contaminated Lou soil and mixed Cu and Pb contaminated Lou soil under different conditions such as reaction time, mass concentration of saponin, pH, concentration of background electrolyte and leaching times. The results showed that the maximum leaching removal effect of Cu and Pb in contaminated Lou soil was achieved by complexation of the heavy metals with saponin micelle, when the mass concentration of saponin solution was 50 g x L(-1), pH was 5.0, the reaction time was 240 min, and there was no background electrolyte. In single and mixed contaminated Lou soil, the leaching percentages of Cu were 29.02% and 25.09% after a single leaching with 50 g x L(-1) saponin under optimal condition, while the single leaching percentages of Pb were 31.56% and 28.03%, respectively. The result indicated the removal efficiency of Pb was more significant than that of Cu. After 4 times of leaching, the cumulative leaching percentages of Cu reached 58.92% and 53.11%, while the cumulative leaching percentages of Pb reached 77.69% and 65.32% for single and mixed contaminated Lou soil, respectively. The fractionation results of heavy metals in soil before and after a single leaching showed that the contents of adsorbed and exchangeable Cu and Pb increased in the contaminated soil, while the carbonate-bound, organic bound and sulfide residual Cu and Pb in the contaminated Lou soil could be effectively removed by saponin.

Spent lithium-ion battery recycling - Reductive ammonia leaching of metals from cathode scrap by sodium sulphite.

PubMed

Zheng, Xiaohong; Gao, Wenfang; Zhang, Xihua; He, Mingming; Lin, Xiao; Cao, Hongbin; Zhang, Yi; Sun, Zhi

2017-02-01

Recycling of spent lithium-ion batteries has attracted wide attention because of their high content of valuable and hazardous metals. One of the difficulties for effective metal recovery is the separation of different metals from the solution after leaching. In this research, a full hydrometallurgical process is developed to selectively recover valuable metals (Ni, Co and Li) from cathode scrap of spent lithium ion batteries. By introducing ammonia-ammonium sulphate as the leaching solution and sodium sulphite as the reductant, the total selectivity of Ni, Co and Li in the first-step leaching solution is more than 98.6% while it for Mn is only 1.36%. In detail understanding of the selective leaching process is carried out by investigating the effects of parameters such as leaching reagent composition, leaching time (0-480min), agitation speed (200-700rpm), pulp density (10-50g/L) and temperature (323-353K). It was found that Mn is primarily reduced from Mn 4+ into Mn 2+ into the solution as [Formula: see text] while it subsequently precipitates out into the residue in the form of (NH 4 ) 2 Mn(SO 3 ) 2 ·H 2 O. Ni, Co and Li are leached and remain in the solution either as metallic ion or amine complexes. The optimised leaching conditions can be further obtained and the leaching kinetics is found to be chemical reaction control under current leaching conditions. As a result, this research is potentially beneficial for further optimisation of the spent lithium ion battery recycling process after incorporating with metal extraction from the leaching solution. Copyright © 2016 Elsevier Ltd. All rights reserved.

Spatial distribution of solute leaching with snowmelt and irrigation: measurements and simulations

NASA Astrophysics Data System (ADS)

Schotanus, D.; van der Ploeg, M. J.; van der Zee, S. E. A. T. M.

2013-04-01

Transport of a tracer and a degradable solute in a heterogeneous soil was measured in the field, and simulated with several transient and steady state infiltration rates. Leaching surfaces were used to investigate the solute leaching in space and time simultaneously. In the simulations, a random field for the scaling factor in the retention curve was used for the heterogeneous soil, which was based on the spatial distribution of drainage in an experiment with a multi-compartment sampler. As a criterion to compare the results from simulations and observations, the sorted and cumulative total drainage in a cell was used. The effect of the ratio of the infiltration rate over the degradation rate on leaching of degradable solutes was investigated. Furthermore, the spatial distribution of the leaching of degradable and non-degradable solutes was compared. The infiltration rate determines the amount of leaching of the degradable solute. This can be partly explained by a decreasing travel time with an increasing infiltration rate. The spatial distribution of the leaching also depends on the infiltration rate. When the infiltration rate is high compared to the degradation rate, the leaching of the degradable solute is similar as for the tracer. The fraction of the pore space of the soil that contributes to solute leaching increases with an increasing infiltration rate. This fraction is similar for a tracer and a degradable solute. With increasing depth, the leaching becomes more homogeneous, as a result of dispersion. The spatial distribution of the solute leaching is different under different transient infiltration rates, therefore, also the amount of leaching is different. With independent stream tube approaches, this effect would be ignored.

Spatial distribution of solute leaching with snowmelt and irrigation: measurements and simulations

NASA Astrophysics Data System (ADS)

Schotanus, D.; van der Ploeg, M. J.; van der Zee, S. E. A. T. M.

2012-12-01

Transport of a tracer and a degradable solute in a heterogeneous soil was measured in the field, and simulated with several transient and steady state infiltration rates. Leaching surfaces were used to investigate the solute leaching in space and time simultaneously. In the simulations, a random field for the scaling factor in the retention curve was used for the heterogeneous soil, which was based on the spatial distribution of drainage in an experiment with a multi-compartment sampler. As a criterion to compare the results from simulations and observations, the sorted and cumulative total drainage in a cell was used. The effect of the ratio of the infiltration rate over the degradation rate on leaching of degradable solutes was investigated. Furthermore, the spatial distribution of the leaching of degradable and non-degradable solutes was compared. The infiltration rate determines the amount of leaching of the degradable solute. This can be partly explained by a decreasing travel time with an increasing infiltration rate. The spatial distribution of the leaching also depends on the infiltration rate. When the infiltration rate is high compared to the degradation rate, the leaching of the degradable solute is similar as for the tracer. The fraction of the soil that contributes to solute leaching increases with an increasing infiltration rate. This fraction is similar for a tracer and a degradable solute. With increasing depth, the leaching becomes more homogeneous, as a result of dispersion. The spatial distribution of the solute leaching is different under different transient infiltration rates, therefore also the amount of leaching is different. With independent stream tube approaches, this effect would be ignored.

Improving International Marketing Programs to Reflect Global Complexity and Risk: Curriculum Drivers and Constraints

ERIC Educational Resources Information Center

Vos, Lynn

2013-01-01

This article looks at the curriculum redesign of a master's-level program in international marketing from a UK perspective. In order to ensure that the program would be more fit-for-purpose for future managers working under conditions of complexity, uncertainty, and within regimes often very different from the home market, the team began the…

Bertolette Selected as EHS Champion of Safety | Poster

Cancer.gov

Dan Bertolette has been selected as the most recent NCI at Frederick Champion of Safety, as part of the Champions of Safety Program sponsored by the Environment, Health, and Safety Program (EHS). The goal of the program, which began last year, is to raise awareness and promote a culture of safety by showing NCI at Frederick staff at work in their respective workplaces,

Peering around the Corner: Analyzing State Efforts to Link Teachers to the Programs That Prepared Them

ERIC Educational Resources Information Center

Mitchel, Ashley LiBetti; Aldeman, Chad

2016-01-01

States, programs, and schools have long focused on the inputs of teacher preparation--the rules for candidates and the preparation programs they attend--because inputs were thought to predict teacher effectiveness, and because they were often the best option available. But in the early 2000s, policymakers began trying to evaluate preparation…

Helping Community College Students Cope with Financial Emergencies: Lessons from the Dreamkeepers and Angel Fund Emergency Financial Aid Programs

ERIC Educational Resources Information Center

Geckeler, Christian

2008-01-01

Lumina Foundation for Education created the Dreamkeepers and Angel Fund Emergency Financial Aid Programs to assist community college students who are at risk of dropping out because of unexpected financial crises. Both programs are multiyear pilot projects that began in 2005 and are administered by Scholarship America and the American Indian…

Student Perceptions of the Value of a University Laptop Program

ERIC Educational Resources Information Center

Orr, Claudia; Sherony, Bruce; Steinhaus, Carol

2008-01-01

In the fall of 2000, when a mandatory laptop program was initiated at a Midwest regional university, a faculty research team began a longitudinal study to determine student perceptions of the value of the program. Value was defined as usefulness of the computer, reasonable price for the computer and the quality of the computer. A survey of 1,000…

ScholarshipBuilder Program, Second Annual Report 1989-1990. Report No. 10, Vol. 25.

ERIC Educational Resources Information Center

Ruffin, Minnie R.; And Others

The ScholarshipBuilder Program, an adopt-a-class program, began in November 1988 to encourage selected first-grade students to stay in school until graduation in the year 2000. Scholarships will be provided by Merrill Lynch, Incorporated, for students who go on to college, and a one-time stipend will be provided to students who enter the military…

The visual management system of the Forest Service, USDA

Treesearch

Warren R. Bacon

1979-01-01

The National Forest Landscape Management Program began, as a formal program, at a Servicewide meeting in St. Louis in 1969 in response to growing agency and public concern for the visual resource. It is now an accepted part of National Forest management and is supported by a large and growing foundation of handbooks, research papers, and audio/visual programs. This...

Recycling process for recovery of gallium from GaN an e-waste of LED industry through ball milling, annealing and leaching

DOE Office of Scientific and Technical Information (OSTI.GOV)

Swain, Basudev, E-mail: swain@iae.re.kr; Mishra, Chinmayee; Kang, Leeseung

Waste dust generated during manufacturing of LED contains significant amounts of gallium and indium, needs suitable treatment and can be an important resource for recovery. The LED industry waste dust contains primarily gallium as GaN. Leaching followed by purification technology is the green and clean technology. To develop treatment and recycling technology of these GaN bearing e-waste, leaching is the primary stage. In our current investigation possible process for treatment and quantitative leaching of gallium and indium from the GaN bearing e-waste or waste of LED industry dust has been developed. To recycle the waste and quantitative leaching of gallium,more » two different process flow sheets have been proposed. In one, process first the GaN of the waste the LED industry dust was leached at the optimum condition. Subsequently, the leach residue was mixed with Na{sub 2}CO{sub 3}, ball milled followed by annealing, again leached to recover gallium. In the second process, the waste LED industry dust was mixed with Na{sub 2}CO{sub 3}, after ball milling and annealing, followed acidic leaching. Without pretreatment, the gallium leaching was only 4.91 w/w % using 4 M HCl, 100 °C and pulp density of 20 g/L. After mechano-chemical processing, both these processes achieved 73.68 w/w % of gallium leaching at their optimum condition. The developed process can treat and recycle any e-waste containing GaN through ball milling, annealing and leaching. - Highlights: • Simplest process for treatment of GaN an LED industry waste developed. • The process developed recovers gallium from waste LED waste dust. • Thermal analysis and phase properties of GaN to Ga{sub 2}O{sub 3} and GaN to NaGaO{sub 2} revealed. • Solid-state chemistry involved in this process reported. • Quantitative leaching of the GaN was achieved.« less

Leaching standards for mineral recycling materials--a harmonized regulatory concept for the upcoming German Recycling Decree.

PubMed

Susset, Bernd; Grathwohl, Peter

2011-02-01

In this contribution we give a first general overview of results of recent studies in Germany which focused on contaminant leaching from various materials and reactive solute transport in the unsaturated soil zone to identify the key factors for groundwater risk assessment. Based on these results we developed new and improved existing methods for groundwater risk assessment which are used to derive a new regulatory concept for the upcoming "Decree for the Requirements of the Use of Alternative Mineral Building Materials in Technical Constructions and for the Amendment of the Federal Soil Protection and Contaminated Sites Ordinance" of the German Federal Ministry of Environment. The new concept aims at a holistic and scientifically sound assessment of the use of mineral recycling materials (e.g., mineral waste, excavated soils, slag and ashes, recycling products, etc.) in technical constructions (e.g., road dams) and permanent applications (e.g., backfilling and landscaping) which is based on a mechanistic understanding of leaching and transport processes. Fundamental for risk assessment are leaching standards for the mineral recycling materials. For each application of mineral recycling materials specific maximum concentrations of a substance in the seepage water at the bottom of an application were calculated. Technical boundary conditions and policy conventions derived from the "German precautionary groundwater and soil protection policy" were accounted to prevent adverse environmental effects on the media soil and groundwater. This includes the concentration decline of highly soluble substances (e.g., chloride and sulphate), retardation or attenuation of solutes, accumulation of contaminants in sub-soils and the hydraulic properties of recycling materials used for specific applications. To decide whether the use of a mineral recycling material is possible in a specific application, the leaching qualities were evaluated based on column percolation tests with various samples and compared with application-specific maximum concentrations. In the upcoming federal decree this simplified concept is realized using detailed tables which classify the leaching quality of mineral recycling materials and demonstrate potential application. A quality assurance system will be mandatory which defines specific testing programs (material properties and limit concentrations to be tested, number and schedule of testing) for the different mineral recycling materials using standardized methods (column percolation test). Copyright © 2010 Elsevier Ltd. All rights reserved.

The Information Ambassadors: The 1989-90 Library/Book Fellows.

ERIC Educational Resources Information Center

American Library Association, Chicago, IL.

This report begins by describing the American Library Association (ALA) Library/Book Fellows program, which began with a grant from the U.S. Information Agency in 1986. The program has a threefold purpose: (1) to increase international understanding through the establishment of professional and personal relationships and the accomplishment of…

Identification of parental program structures for deterring adolescent drinking and driving. Volume 1, Report on focus groups with parents

DOT National Transportation Integrated Search

1989-11-01

The objective of this project was to determine the feasibility of developing programs to assist parents in preventing driving after drinking among their children. The project began with a literature review to learn what information about developing p...

Discovering and Analyzing Network Function and Structure

DTIC Science & Technology

2015-07-08

currently assigned to the award James Lawton Reporting Period Start Date 04/01/2012 Reporting Period End Date 03/31/2015 Abstract This award has supported...AFOSR Program Manager, if any: The program manager is now James Lawton . When this award began, it was Robert Bonneau. Extensions granted or

Apraxia of Speech: The Effectiveness of a Treatment Regimen.

ERIC Educational Resources Information Center

Dworkin, James Paul; And Others

1988-01-01

A treatment program is described which successfully improved the speech of a 57-year-old apraxic patient. The program was composed of physiologic (nonspeech) and phonetic (articulatory) tasks that began with oroneuromotor control activities and progressed to consonant-vowel syllable, word, and sentence drills, with all activities paced by a…

Implementing Year-Round School--Monroe Style.

ERIC Educational Resources Information Center

Cruz, John

Planning for conversion to a year-round school in James Monroe School, Madera, California, began in 1984 as educators and community faced the fact that continued enrollment increases had reached a critical point. This report describes program development and implementation; an appendix with program worksheets comprises over one-half of the…

The Information Ambassadors: The 1990-91 Library/Book Fellows.

ERIC Educational Resources Information Center

American Library Association, Chicago, IL.

The American Library Association (ALA) Library/Book Fellows program began in 1986 with a grant from the U.S. Information Agency. The program's purpose is threefold: (1) to increase international understanding through the establishment of professional and personal relationships and the accomplishment of mutual goals; (2) to promote international…

Health Promotion Program.

ERIC Educational Resources Information Center

McClary, Cheryl

The Health Promotion Program began with establishment of a one-credit course in health promotion and wellness and the training of family practice residents at the Mountain Area Health Education Center to serve as lab leaders in the course. The course later became part of the university's general education requirements. In addition, a health…

Changing the Face of STEM with Stormwater Research

ERIC Educational Resources Information Center

Musavi, Mohamad; Friess, Wilhelm A.; James, Cary; Isherwood, Jennifer C.

2018-01-01

Background: The University of Maine Stormwater Management and Research Team (SMART) program began in 2014 with the goal of creating a diverse science-technology-engineering-math (STEM) pathway with community water research. The program engages female and underrepresented minority high school students in locally relevant STEM research. It focuses…

Quality Assurance Program Description

DOE Office of Scientific and Technical Information (OSTI.GOV)

Halford, Vaughn Edward; Ryder, Ann Marie

Effective May 1, 2017, led by a new executive leadership team, Sandia began operating within a new organizational structure. National Technology and Engineering Solutions of Sandia (Sandia’s) Quality Assurance Program (QAP) was established to assign responsibilities and authorities, define workflow policies and requirements, and provide for the performance and assessment of work.

Project T.E.A.M. (Technical Education Advancement Modules). Final Report.

ERIC Educational Resources Information Center

Greenville Technical Coll., SC.

Project TEAM (Technical Education Advancement Modules), a cooperative demonstration program for high technology training, created an introductory technical training program and a consumer education package emphasizing the benefits of technical training. The curriculum and training focus of the project began with an assessment of employee needs in…

Developing Leaders for the 21st Century

ERIC Educational Resources Information Center

Phillips, John L.

2005-01-01

This article describes the Leadership Development for the 21st Century: Linking Research, Academics and Extension program that began in June 2005. This 12-month program, designed to explore different models of leadership, develop peer networks, and enhance skills and knowledge in leadership competencies, is specifically for land grand educators…

Leading Change: Curriculum Reform in Graduate Education in the Biomedical Sciences

ERIC Educational Resources Information Center

Dasgupta, Shoumita; Symes, Karen; Hyman, Linda

2015-01-01

The Division of Graduate Medical Sciences at the Boston University School of Medicine houses numerous dynamic graduate programs. Doctoral students began their studies with laboratory rotations and classroom training in a variety of fundamental disciplines. Importantly, with 15 unique pathways of admission to these doctoral programs, there were…

Intermediate-Level Foreign Language Courses for BBA Students.

ERIC Educational Resources Information Center

Ortuno, Manuel J.; Uber, David M.

Following the early success of its inclusion of languages in the master's-level business administration curriculum, Baylor University began to emphasize foreign language study more heavily in its undergraduate business administration program. The revised program, to be fully implemented in 1989, encourages students to choose 11 hours of language…

Laptop Circulation at Eastern Washington University

ERIC Educational Resources Information Center

Munson, Doris; Malia, Elizabeth

2008-01-01

In 2001, Eastern Washington University's Libraries began a laptop circulation program with seventeen laptops. Today, there are 150 laptops in the circulation pool, as well as seventeen digital cameras, eleven digital handycams, and thirteen digital projectors. This article explains how the program has grown to its present size, the growing pains…

Campus Kids Mentoring Program: Fifteen Years of Success

ERIC Educational Resources Information Center

Shepard, Jerri

2009-01-01

This article features Campus Kids, a mentoring program located at Gonzaga University in Spokane, Washington. Gonzaga is a Jesuit University with a strong commitment to social justice and humanistic education. Campus Kids began, in the true sense of a community partnership, as an attempt to connect community resources (potential university…

An Experiment In Field-Based Elementary Teacher Education.

ERIC Educational Resources Information Center

Swann, Margaret H.

The Experimental Program in Elementary Education (EXEL) at Shepherd College in West Virginia began in 1973 with authorization by the West Virginia State Department of Education. The program was developed with the hope of producing more confident and competent teachers. EXEL provides continuous field experience from the second semester of the…

RELATIVE LEACHING AND AQUATIC TOXICITY OF PRESSURE-TREATED WOOD PRODUCTS USING BATCH LEACHING TESTS

EPA Science Inventory

Samples of southern yellow pine dimensional lumber, each treated with one of five different waterborne chemical preservatives, were leached using 18-hour batch leaching tests. The wood preservatives included chromated copper arsenate (CCA), alkaline copper quaternary (ACQ), coppe...

Leaching of Titanium and Silicon from Low-Grade Titanium Slag Using Hydrochloric Acid Leaching

NASA Astrophysics Data System (ADS)

Zhao, Longsheng; Wang, Lina; Qi, Tao; Chen, Desheng; Zhao, Hongxin; Liu, Yahui; Wang, Weijing

2018-05-01

Acid-leaching behaviors of the titanium slag obtained by selective reduction of vanadium-bearing titanomagnetite concentrates were investigated. It was found that the optimal leaching of titanium and silicon were 0.7% and 1.5%, respectively. The titanium and silicon in the titanium slag were firstly dissolved in the acidic solution to form TiO2+ and silica sol, and then rapidly reprecipitated, forming hydrochloric acid (HCl) leach residue. Most of the silicon presented in the HCl leach residue as floccules-like silica gel, while most of the titanium was distributed in the nano-sized rod-like clusters with crystallite refinement and intracrystalline defects, and, as such, 94.3% of the silicon was leached from the HCl leach residue by alkaline desilication, and 96.5% of the titanium in the titanium-rich material with some rutile structure was then digested by the concentrated sulfuric acid. This provides an alternative route for the comprehensive utilization of titanium and silicon in titanium slag.

A long-term static immersion experiment on the leaching behavior of heavy metals from waste printed circuit boards.

PubMed

Zhao, Guo-Hua; Luo, Xing-Zhang; Chen, Gui; Zhao, Yong-Jun

2014-08-01

Printed circuit boards (PCBs) are the main components of electrical and electronic equipment (EEE). Waste PCBs contain several kinds of heavy metals, including Cu, Pb and Zn. We characterize the leaching of heavy metals (Cu, Pb, Zn and Ni) from waste PCBs in a pH range of 3.0 to 5.6 using a novel approach based on batch pH-static leaching experiments in this work. The results indicate that the leaching behavior of Cu, Pb, Zn and Ni is strongly dependent on pH. Leaching behavior also varies with different pH values and leaching times. The maximum concentrations of Cu, Pb, Zn and Ni in leachate from waste PCBs were 335.00, 17.57, 2.40 and 2.33 mg L(-1), respectively. The highest Pb, Ni, and Cu concentrations leached significantly exceeded the European Union waste-acceptance limit values with respect to inert waste landfills. The leaching of metals follows the shrinking core model with surface reaction control.

U.S. Geological Survey Field Leach Test for Assessing Water Reactivity and Leaching Potential of Mine Wastes, Soils, and Other Geologic and Environmental Materials

USGS Publications Warehouse

Hageman, Philip L.

2007-01-01

The U. S. Geological Survey (USGS) has developed a fast (5-minute), effective, simple, and cost-effective leach test that can be used to simulate the reactions that occur when materials are leached by water. The USGS Field Leach Test has been used to predict, assess, and characterize the geochemical interactions between water and a broad variety of geologic and environmental matrices. Examples of some of the samples leached include metal mine wastes, various types of dusts, biosolids (processed sewage sludge), flood and wetland sediments, volcanic ash, forest-fire burned soils, and many other diverse matrices. The Field Leach Test has been an integral part of these investigations and has demonstrated its value as a geochemical characterization tool. It has enabled investigators to identify which constituents are water reactive, soluble, mobilized, and made bioaccessible because of leaching by water, and to understand potential impacts of these interactions on the surrounding environment.

Factors influencing the Zn and Mn extraction from pyrometallurgical sludge in the steel manufacturing industry.

PubMed

Mocellin, J; Mercier, G; Morel, J L; Blais, J F; Simonnot, M O

2015-08-01

In this laboratory study, a process has been developed for selectively leaching zinc and manganese from pyrometallurgical sludge produced in the steel manufacturing industry. In the first part, the yield of Zn extraction was studied using four factors and four levels of the Box-Behnken response surface design. The optimum conditions for the step of Zn leaching were determined to be a sulfuric acid concentration of 0.25 mol/L, a pulp density of 10%, an extraction temperature of 20 °C, and three stages of leaching. Under such conditions, 75% of the Zn should be leached. For Mn leaching, the optimum conditions were determined to be a sulfuric acid concentration of 0.25 mol/L, a Na2S2O5/Mn stoichiometry of 1, a leaching time of 120 min and two leaching steps. In this case, 100% of the Mn should be leached. Copyright © 2015 Elsevier Ltd. All rights reserved.

The leaching of lead from lead-based paint in landfill environments.

PubMed

Wadanambi, Lakmini; Dubey, Brajesh; Townsend, Timothy

2008-08-30

Lead leaching from lead-based paint (LBP) was examined using standardized laboratory protocols and tests with leachate from actual and simulated landfill environments. Two different LBP samples were tested; leaching solutions included leachates from three municipal solid waste (MSW) landfills and three construction and demolition (C&D) debris landfills. The toxicity characteristic leaching procedure (TCLP) and the synthetic precipitation leaching procedure (SPLP) were also performed. Lead concentrations were many times higher using the TCLP compared to the SPLP and the landfill leachates. No significant difference (alpha=0.05) was observed in leached lead concentrations from the MSW landfill and C&D debris landfill leachates. The impact of other building materials present in LBP debris on lead leaching was examined by testing mixtures of LBP (2%) and different building materials (98%; steel, wood, drywall, concrete). The type of substrate present impacted lead leaching results, with concrete demonstrating the most dramatic impact; the lowest lead concentrations were measured in the presence of concrete under both TCLP and SPLP extractions.

Nitrate leaching in a winter wheat-summer maize rotation on a calcareous soil as affected by nitrogen and straw management.

PubMed

Huang, Tao; Ju, Xiaotang; Yang, Hao

2017-02-08

Nitrate leaching is one of the most important pathways of nitrogen (N) loss which leads to groundwater contamination or surface water eutrophication. Clarifying the rates, controlling factors and characteristics of nitrate leaching is the pre-requisite for proposing effective mitigation strategies. We investigated the effects of interactions among chemical N fertilizer, straw and manure applications on nitrogen leaching in an intensively managed calcareous Fluvo-aquic soil with winter wheat-summer maize cropping rotations on the North China Plain from October 2010 to September 2013 using ceramic suction cups and seepage water calculations based on a long-term field experiment. Annual nitrate leaching reached 38-60 kg N ha -1 from conventional N managements, but declined by 32-71% due to optimum N, compost manure or municipal waste treatments, respectively. Nitrate leaching concentrated in the summer maize season, and fewer leaching events with high amounts are the characteristics of nitrate leaching in this region. Overuse of chemical N fertilizers, high net mineralization and nitrification, together with predominance of rainfall in the summer season with light soil texture are the main controlling factors responsible for the high nitrate leaching loss in this soil-crop-climatic system.

Process optimization and leaching kinetics of zinc and manganese metals from zinc-carbon and alkaline spent batteries using citric acid reagent

NASA Astrophysics Data System (ADS)

Yuliusman; Amiliana, R. A.; Wulandari, P. T.; Huda, M.; Kusumadewi, F. A.

2018-03-01

Zn-Carbon and Alkaline spent batteries contains heavy metals, such as zinc and manganese, which can causes environmental problem if not handled properly. Usually the recovery of these metals were done by leaching method using strong acid, but the use of strong acids as leaching reagents can be harmful to the environment. This paper concerns the recovery of Zn and Mn metals from Zn-C and alkaline spent batteries with leaching method using citric acid as the environmental friendly leaching reagent. The leaching conditions using citric acid were optimized and the leaching kinetics of Zn and Mn in citric acid solution was investigated. The leaching of 89.62% Zn and 63.26% Mn was achieved with 1.5 M citric acid, 90°C temperature, and 90 minutes stirring time. Kinetics data for the dissolution of Zn showed the best fit to chemical control shrinking core model, while the diffusion controlled model was suitable for the dissolution of Mn kinetics data. The activation energy of 6.12 and 1.73 kcal/mol was acquired for the leaching of Zn and Mn in the temperature range 60°C-90°C.

Coatings to reduce wood preservative leaching.

PubMed

Nejad, Mojgan; Cooper, Paul

2010-08-15

The efficiency of semitransparent penetrating stains to reduce leaching of wood preservative components was evaluated. Five commercial wood deck finishes were applied to untreated and chromated copper arsenate (CCA), alkaline copper quat (ACQ), and copper azole (CA) treated wood, and leachates were collected and analyzed during 3 years of natural weathering exposure in Toronto, Canada. All stains evaluated effectively reduced the cumulative leaching of all inorganic preservative components by about 60% on average. Although most coatings showed significant film degradation starting around 12 months, the reduced leaching persisted even after 3 years. This suggests that temporary protection of wood with a coating during the early stages of use resulted in long-term reduction in preservative leaching potential. A two-week screening leaching test was able to predict the long-term leaching performance of different coatings reasonably well. Cured coating glass transition temperature (Tg) and liquid coating viscosity were the most important variables affecting a leaching prediction model. To effectively reduce leaching of preservative components from treated wood, coatings should have Tg low enough to withstand stresses caused by freezing in winter and have adequate viscosity to form a barrier film layer on the wood surface.

Microfluidic Platform for High-throughput Screening of Leach Chemistry.

PubMed

Yang, Die; Priest, Craig

2018-06-20

We demonstrate an optofluidic screening platform for studying thiosulfate leaching of Au in a transparent microchannel. The approach permits in situ (optical) monitoring of Au thickness, reduced reagent use, rapid optimization of reagent chem-istry, screening of temperature, and determination of the activation energy. The results demonstrate the critical importance of the (1) preparation and storage of the leach solution, (2) deposition and annealing of the Au film, and (3) lixiviant chem-istry. The density of sputter deposited Au films decreased with depth resulting in accelerating leach rates during experiments. Atomic leach rates were determined and were constant throughout each experiment. Annealing above 270 °C was found to prevent leaching, which can be attributed to diffusion of the chromium adhesion layer into the Au film. The optofluidic analysis revealed leach rates that are sensitive to the stoichiometric ratio of thiosulphate, ammonia and copper in the leach solution, and optimized for 10 mM CuSO 4 , 1 M Na 2 S 2 O 3 and 1 M NH 4 OH. The temperature dependence of the leach rate gave an apparent activation energy of ~ 40 kJ.mol -1 , based on Arrhenius' relationship.

Nitrate leaching in a winter wheat-summer maize rotation on a calcareous soil as affected by nitrogen and straw management

NASA Astrophysics Data System (ADS)

Huang, Tao; Ju, Xiaotang; Yang, Hao

2017-02-01

Nitrate leaching is one of the most important pathways of nitrogen (N) loss which leads to groundwater contamination or surface water eutrophication. Clarifying the rates, controlling factors and characteristics of nitrate leaching is the pre-requisite for proposing effective mitigation strategies. We investigated the effects of interactions among chemical N fertilizer, straw and manure applications on nitrogen leaching in an intensively managed calcareous Fluvo-aquic soil with winter wheat-summer maize cropping rotations on the North China Plain from October 2010 to September 2013 using ceramic suction cups and seepage water calculations based on a long-term field experiment. Annual nitrate leaching reached 38-60 kg N ha-1 from conventional N managements, but declined by 32-71% due to optimum N, compost manure or municipal waste treatments, respectively. Nitrate leaching concentrated in the summer maize season, and fewer leaching events with high amounts are the characteristics of nitrate leaching in this region. Overuse of chemical N fertilizers, high net mineralization and nitrification, together with predominance of rainfall in the summer season with light soil texture are the main controlling factors responsible for the high nitrate leaching loss in this soil-crop-climatic system.

Implementation of the Leaching Environmental Assessment ...

EPA Pesticide Factsheets

New leaching tests are available in the U.S. for developing more accurate source terms for use in fate and transport models. For beneficial use or disposal, the use of the leaching environmental assessment framework (LEAF) will provide leaching results that reflect field conditions reflecting either use of disposal of the material or waste. To provide overview of the implementation of new leaching tests for presentation at the MEGA symposium which is for the coal-fired power industry

Novel Approach for Enhanced Scandium and Titanium Leaching Efficiency from Bauxite Residue with Suppressed Silica Gel Formation.

PubMed

Alkan, Gözde; Yagmurlu, Bengi; Cakmakoglu, Seckin; Hertel, Tobias; Kaya, Şerif; Gronen, Lars; Stopic, Srecko; Friedrich, Bernd

2018-04-04

The need of light weight alloys for future transportation industry puts Sc and Ti under a sudden demand. While these metals can bring unique and desired properties to alloys, lack of reliable sources brought forth a supply problem which can be solved by valorization of the secondary resources. Bauxite residue (red mud), with considerable Ti and Sc content, is a promising resource for secure supply of these metals. Due to drawbacks of the direct leaching route from bauxite residue, such as silica gel formation and low selectivity towards these valuable metals, a novel leaching process based on oxidative leaching conditions, aiming more efficient and selective leaching but also considering environmental aspects via lower acid consumption, was investigated in this study. Combination of hydrogen peroxide (H 2 O 2 ) and sulfuric acid (H 2 SO 4 ) was utilized as the leaching solution, where various acid concentrations, solid-to-liquid ratios, leaching temperatures and times were examined in a comparative manner. Leaching with 2.5 M H 2 O 2 : 2.5 M H 2 SO 4 mixture at 90 °C for 30 min was observed to be the best leaching conditions with suppressed silica gel formation and the highest reported leaching efficiency with high S/L ratio for Sc and Ti; 68% and 91%; respectively.

Comparative study on copper leaching from waste printed circuit boards by typical ionic liquid acids.

PubMed

Chen, Mengjun; Huang, Jinxiu; Ogunseitan, Oladele A; Zhu, Nengming; Wang, Yan-min

2015-07-01

Waste printed circuit boards (WPCBs) are attracting increasing concerns because the recovery of its content of valuable metallic resources is hampered by the presence of hazardous substances. In this study, we used ionic liquids (IL) to leach copper from WPCBs. [BSO3HPy]OTf, [BSO3HMIm]OTf, [BSO4HPy]HSO4, [BSO4HMim]HSO4 and [MIm]HSO4 were selected. Factors that affect copper leaching rate were investigated in detail and their leaching kinetics were also examined with the comparison of [Bmim]HSO4. The results showed that all six IL acids could successfully leach copper out, with near 100% recovery. WPCB particle size and leaching time had similar influences on copper leaching performance, while IL acid concentration, hydrogen peroxide addition, solid to liquid ratio, temperature, showed different influences. Moreover, IL acid with HSO4(-) was more efficient than IL acid with CF3SO3(-). These six IL acids indicate a similar behavior with common inorganic acids, except temperature since copper leaching rate of some IL acids decreases with its increase. The results of leaching kinetics studies showed that diffusion plays a more important role than surface reaction, whereas copper leaching by inorganic acids is usually controlled by surface reaction. This innovation provides a new option for recovering valuable materials such as copper from WPCBs. Copyright © 2015 Elsevier Ltd. All rights reserved.

An active dealkalization of red mud with roasting and water leaching.

PubMed

Zhu, Xiaobo; Li, Wang; Guan, Xuemao

2015-04-09

The research has focused on the dealkalization of red mud after active roasting and water leaching, which is obtained from bauxite during alumina production. The main factors such as roasting temperature, roasting time, water leaching stage, leaching temperature, leaching reaction time and liquid to solid ratio were investigated. The mechanism of dealkalization was in-depth studied by using ICP-AES, XRD, TG-DSC, SEM-EDS and leaching kinetic. The results show that the dealkalization rate reached 82% under the condition of roasting temperature of 700 °C, roasting time of 30 min, four stage water leaching, liquid to solid ratio of 7 mL/g, leaching temperature of 90 °C and reaction time of 60 min. The diffraction peak of Na6CaAl6Si6(CO3)O24 · 2H2O in red mud was decreased during the active roasting process, whereas the mineral phases of NaOH · H2O and Na2Ca(CO3)2 were appeared. The content of alkali obviously decreased and the grade of other elements increased during the process of active roasting and water leaching, which was in favor of next application process of red mud. The water leaching was controlled by internal diffusion of SCM and the apparent activation energy was 22.63 kJ/mol. Copyright © 2014 Elsevier B.V. All rights reserved.

Comparison of leaching characteristics of heavy metals from bottom and fly ashes in Korea and Japan.

PubMed

Shim, Young-Sook; Rhee, Seung-Whee; Lee, Woo-Keun

2005-01-01

The objective of this research was to compare the leaching characteristics of heavy metals such as cadmium, chromium, copper, nickel, lead, etc., in Korean and Japanese municipal solid waste incineration (MSWI) ash. The rate of leaching of heavy metal was measured by KSLT and JTL-13, and the amount of heavy metals leached was compared with the metal content in each waste component. Finally, bio-availability testing was performed to assess the risks associated with heavy metals leached from bottom ash and fly ash. From the results, the value of neutralization ability in Japanese fly ash was four times higher than that in Korean fly ash. The reason was the difference in the content of Ca(OH)(2) in fly ash. The amount of lead leached exceeded the regulatory level in both Japanese and Korean fly ash. The rate of leaching was relatively low in ash with a pH in the range of 6-10. The bio-availability test in fly ash demonstrated that the amount of heavy metals leached was Pb>Cd>Cr, but the order was changed to Pb>Cr>Cd in the bottom ash. The leaching concentration of lead exceeded the Japanese risk level in all fly ashes from the two countries, but the leaching concentration of cadmium exceeded the regulatory level in Korean fly ash only.

Gold leaching by organic base polythionates: new non-toxic and secure technology.

PubMed

Smolyaninov, Vladislav; Shekhvatova, Galina; Vainshtein, Mikhail

2014-01-01

The article present a review on own experimental and some published data which are related with the gold leaching. It is well-known that the most common and usual process of the leaching with cyanide can be dangerous, needs a great water consumption, and additional costs for remediation of the poisoned and toxic sites. The experimental data described production of poythionates which are not toxic but perspective for the prosperous gold leaching. The paper dedicated to the safe gold leaching with thiosulfates and organic salts of polythionic acids (organic base polythionates). The method of production of these polythionates based on the Smolyaninov reaction is described in stages and in details for the first time. Possible application of the polythionates application in the gold leaching is discussed and its advantages are compared with the gold leaching by cyanation.

Clinical services provided by staff pharmacists in a community hospital.

PubMed

Garrelts, J C; Smith, D F

1990-09-01

A program for developing staff pharmacists' clinical skills and documenting pharmacists' clinical interventions in a large community teaching hospital is described. A coordinator hired in 1984 to develop clinical pharmacy services began a didactic and experiential program for baccalaureate-level staff pharmacists. Fourteen educational modules are supplemented by journal and textbook articles and small-group discussions of clinical cases, and the clinical coordinator provides individual training on the patient-care units for each pharmacist. Monitoring of clinical pharmacy services began in June 1987; each intervention provided by a pharmacist is recorded on a specially designed form. A target-drug program is used to document cost avoidance achieved through clinical services. Information collected through these monitoring activities is used to educate the pharmacy staff, shared with the pharmacy and therapeutics committee, and used to monitor prescribing patterns of individual physicians. The data are used in the hospital's productivity-monitoring system. All pharmacists who were on staff in 1984 have completed the educational modules, and all new employees are in the process. Since monitoring began, the number of clinical interventions has averaged 2098 per month. Cost avoidance has averaged $9306 per month. Over a five-year period, the development of staff pharmacists' clinical services raised the level of professional practice, produced substantial cost avoidance, and increased the number of pharmacist interventions in medication use.

Leaching kinetic of Nd. Y, Pr and Sm in rare earth hydroxide (REOH) use nitric acid

NASA Astrophysics Data System (ADS)

Purwani, MV; Suyanti

2018-02-01

The purpose of this study were to determine the order of reaction, rate reaction constant and activation energy of reaction Y(OH)3, Nd(OH)3, Pr(OH)3 and Sm(OH)3 with HNO3. The rate reaction constant is necessary to determine the residence time in the design of continuously stirred tank reactor (CSTR). The studied parameters were leaching temperature (60 - 90 °C) and leaching time (0-15 minutes). From the resulting data can be concluded that the leaching process were strongly influenced by the time and temperature process. Leaching rare earth hydroxide (REOH) using nitric acid follows second order. At leaching 10 grams of REOH using 40 ml HNO3 0.0576 mol were obtained maximum conversion at 90 °C and leaching time 15 minutes for Y was 0.95 (leaching efficiency was 95%), for Nd was 0.97 ( leaching efficiency was 97%), for Pr was 0.94 (leaching efficiency was 94%) and for Sm was 0.94 (leaching efficiency was 94%). The largest activation energy was Y of 23.34 kJ/mol followed by Pr of 20.00 kJ/mol, Sm of 17.94 kJ/mol and the smallest was Nd of 16.39 kJ/mol. The relationship between the rate constant of the reaction with T for Y was kY = 338.26 e-23,34/RT, for Nd was kNd = 33.69 e -16,39 / RT, for Pr was kPr = 102.04 e-20 / RT and for Sm adalah was kSm = 50.16 e-17,94/RT

COMPARATIVE EVALUATION OF SHORT-TERM LEACH TESTS FOR HEAVY METAL RELEASE FROM MINERAL PROCESSING WASTE

EPA Science Inventory

Evaluation of metal leaching using a single leach test such as the Toxicity Characteristic Leaching Procedure (TCLP) is often questionable. The pH, redox potential (E_h), particle size and contact time are critical variables in controlling metal stability, not accounted...

LEACHING AND DEGRADATION OF 2,4-DICHLOROPHENOXIACETIC ACID, IN COLOMBIA RICE FLOODED SOIL.

PubMed

Huertas, J; Guerrero, J A; Martinez-Cordon, M J

2015-01-01

Rice is mostly cultivated on soil held under flooded conditions. Under these conditions pesticides undergo reductive transformations which are characteristic to rice fields and other anaerobic systems. The present study was undertaken to evaluate the mobility and persistence of 2,4-dichlorophenoxy acetic acid (2,4-D) under laboratory conditions for the rice crop in Espinal, Colombia. A displacement study was performed on a hand packed soil column 30 cm length. After leaching experiment, the soil from column was sliced into six successive sections (5 cm). Methanol acidified (H3PO4 0.25%) extraction was used to determine the herbicide residues in each section. 2,4-D experimental breakthrough curve was analyzed using Stanmod program (inverse problem) to obtain transport parameters. The non-equilibrium physical model fitted well the experimental breakthrough curve. The recovery percent of 2,4-D in leachates was 36.44% after 3.4 pore volumes, and retardation factor was 2.1, indicating low adsorption in that conditions. 2,4-D was rapidly degraded, with DT50 = 11.4 days. The results suggest that 2,4-D under flooded conditions have a high potential for leaching through the soil profile, although the elevated rate of degradation reduced the ground water contamination risk.

Morphology and pH changes in leached solidified/stabilized waste forms

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cheng, K.Y.; Bishop, P.L.

1996-12-31

Leaching of cement-based waste forms in acetic acid solutions with different acidic strengths has been investigated in this work. The examination of the morphology and pH profile along the acid penetration route by an optical microscope and various pH color indicators is reported. A clear-cut leaching boundary, where the pH changes from below 6 in the leached surface layers to above 12 in the unleached waste form, was observed in every leached sample.

Great Salt Lake basins study unit

USGS Publications Warehouse

Waddell, Kidd M.; Baskin, Robert L.

1994-01-01

In 1991, the U.S. Geological Survey (USGS) began implementing a full-scale National Water-Quality Assessment (NAWQA) Program.The long-term goals of the NAWQA Program are to describe the status and trends in the quality of a large, representative part of the Nation’s surface- and ground-water resources and to provide a sound, scientific understanding of the primary natural and human factors that affect the quality of these resources. In meeting these goals, the program will produce a wealth of water-quality information that will be useful to policy makers and managers at Federal, State, and local levels.A major design feature of the NAWQA Program will enable water-quality information at different areal scales to be integrated. A major component of the program is study-unit investigations, which ae the principal building blocks of the program upon which national-level assessment activities will be based. The 60 study-unit investigations that make up the program are hydrologic systems that include principal river basins and aquifer systems throughout the Nation. These study units cover areas from less than 1.000 to greater than 60,000 mi2 and incorporate from about 60 to 70 percent of the Nation’s water use and population served by public water supply. In 1993, assessment activities began in the Great Salt Lake Basins NAWQA study unit.

A Long-term Forest Fertilization Experiment to Understand Ecosystem Responses to Atmospheric Nitrogen Deposition

NASA Astrophysics Data System (ADS)

Baron, J.; Advani, S. M.; Allen, J.; Boot, C.; Denef, K.; Denning, S.; Hall, E.; Moore, J. C.; Reuth, H.; Ryan, M. G.; Shaw, E.

2016-12-01

Long-term field experiments can reveal changes in ecosystem processes that may not be evident in short-term studies. Short-term measurements or experiments may have narrower objectives or unrealistic treatments in order to see a change, whereas long-term studies can reveal complex interactions that take longer to manifest. We report results from a long-term experiment (1996 to present) in subalpine forests to simulate the consequences of sustained atmospheric nitrogen (N) deposition. Loch Vale watershed in Rocky Mountain National Park, the location of the experiment, has received an order of magnitude greater atmospheric N deposition than estimated background since mid-20th Century. Augmenting that, in 1996 we began adding 25 kg NH4NO3 ha-1 yr-1 to three 30m x 30m old-growth Engelmann spruce and subalpine fir plots. Treated stands were matched by nearby controls. N addition caused rapid leaching of nitrate and cations from soils, and increased N mineralization and nitrification rates. These observations in the fertilized plots have been sustained over time. Soluble aluminum concentrations do not differ significantly between fertilized and control plots, but treated soils are now markedly more acidic (pH of 4.7) than original soil and controls (pH of 5.1); further acidification might increase aluminum leaching. Effects on soil carbon were complex, mediated by reductions in total microbial biomass, decreases in arbuscular mychorrizal and saprotropic fungi, and increased potential rates of N enzyme degrading activities. Initial soil C:N of 24 was lower than similar soils in low N deposition stands (C:N of 36). The C:N declined to 22 with treatment. Fertilized plots lost 11% soil C, but the mechanism is unclear. We did not measure changes in C inputs from litter, microbial biomass, or plant uptake, but there was no change in summer CO2 flux, measured in 2003, 2004, and 2014. Leaching of DOC from fertilized plots was elevated throughout the experiment, providing one pathway for C loss. The soil microfauna was dominated by nematodes; plant parasites and bacterial and fungal feeders were more abundant in fertilized plots than in controls, with fewer predaceous and omnivorous nematodes. Overall, N fertilization altered soil biogeochemical characteristics, soil food webs, and C cycling.

National Water Quality Assessment Program; the Santee Basin and coastal drainage, North Carolina and South Carolina

USGS Publications Warehouse

Hughes, W. Brian

1994-01-01

In 1991, the U.S. Geological Survey (USGS), U.S. Department of the Interior, began a National Water-Quality Assessment Program (NAWQA). The long-term goals of NAWQA are to describe the status of and trends in the quality of a large representative part of the Nation's surface- and ground-water resources and to identify all the major factors that affect the quality of these resources. In addressing these goals, NAWQA produces water-quality information that is useful to policymakers and managers at State, Federal, and local levels.NAWQA emphasis is on regional scale water-quality problems. The program does not diminish the need for smaller scale studies and monitoring designed and conducted by State, Federal, and local agencies. NAWQA, however, provides a large-scale framework for conducting many of these activities and an understanding about regional and national water-quality conditions that cannot be acquired from these other programs and studies.Studies of 60 hydrologic systems that include parts of most major river basins and aquifer systems are the building blocks of the national assessment. The areas of the 60 study units range in size from 1,000 to more than 60,000 square miles (mi2) and represent 60 to 70 percent of the Nation's water use and population served by public water supplies. Twenty investigations were begun in 1991, 20 investigations began in 1994, and 20 are planned to begin in 1997. The assessment activities in the Santee River Basin and Coastal Drainage began in 1994.

Influence of microwaves on the leaching kinetics of uraninite from a low grade ore in dilute sulfuric acid.

PubMed

Madakkaruppan, V; Pius, Anitha; T, Sreenivas; Giri, Nitai; Sarbajna, Chanchal

2016-08-05

This paper describes a study on microwave assisted leaching of uranium from a low-grade ore of Indian origin. The host rock for uranium mineralization is chlorite-biotite-muscovite-quartzo-feldspathic schist. The dominant presence of siliceous minerals determined leaching of uranium values in sulfuric acid medium under oxidizing conditions. Process parametric studies like the effect of sulfuric acid concentration (0.12-0.50M), redox potential (400-500mV), particle size (600-300μm) and temperature (35°-95°C) indicated that microwave assisted leaching is more efficient in terms of overall uranium dissolution, kinetics and provide relatively less impurities (Si, Al, Mg and Fe) in the leach liquor compared to conventional conductive leaching. The kinetics of leaching followed shrinking core model with product layer diffusion as controlling mechanism. Copyright © 2016 Elsevier B.V. All rights reserved.

Leaching of a copper flotation concentrate with ammonium persulfate in an autoclave system

NASA Astrophysics Data System (ADS)

Deniz Turan, M.; Soner Altundoğan, H.

2014-09-01

The leaching behavior of a copper flotation concentrate was investigated using ammonium persulfate (APS) in an autoclave system. The decomposition products of APS, active oxygen, and acidic medium were used to extract metals from the concentrate. Leaching experiments were performed to compare the availability of APS as an oxidizing agent for leaching of the concentrate under atmospheric conditions and in an autoclave system. Leaching temperature and APS concentration were found to be important parameters in both leaching systems. Atmospheric leaching studies showed that the metal extractions increased with the increase in APS concentration and temperature (up to 333 K). A similar tendency was determined in the autoclave studies up to 423 K. It was also determined that the metal extractions decreased at temperatures above 423 K due to the passivation of the particle surface by molten elemental sulfur. The results showed that higher copper extractions could be achieved using an autoclave system.

Assessment of Pb, Cd, Cr and Ag leaching from electronics waste using four extraction methods.

PubMed

Keith, Ashley; Keesling, Kara; Fitzwater, Kendra K; Pichtel, John; Houy, Denise

2008-12-01

Heavy metals present in electronic components may leach upon disposal and therefore pose significant environmental hazards. The potential leaching of Pb, Cd, Cr and Ag from PC cathode ray tubes, printed circuit boards (PCBs), PC mice, TV remote controls, and mobile phones was assessed. After controlled crushing, each component was extracted using the Toxicity Characteristic Leaching Procedure (TCLP), EPA Method 1312 (SPLP), NEN 7371 (Dutch Environmental Agency), and DIN S4 (Germany). The TCLP consistently leached the greatest amounts of Pb from all components. The SPLP, NEN 7371 and DIN S4 extracted relatively small amounts of metals compared with the TCLP and were not considered effective as leaching tests for e-waste. The smallest size fraction (< 2 mm) of CRT glass and PCBs leached significantly (p < 0.05) highest Pb via the TCLP. A modified TCLP removed 50.9% more extractable Pb compared with the conventional procedure.

Selective Acidic Leaching of Spent Zinc-Carbon Batteries Followed by Zinc Electrowinning

NASA Astrophysics Data System (ADS)

Shalchian, Hossein; Rafsanjani-Abbasi, Ali; Vahdati-Khaki, Jalil; Babakhani, Abolfazl

2015-02-01

In this work, a selective acidic leaching procedure was employed for recycling zinc from spent zinc-carbon batteries. Leaching experiments were carried out in order to maximize zinc recovery and minimize manganese recovery in diluted sulfuric acid media. Response surface methodology and analysis of variance were employed for experimental design, data analysis, and leaching optimization. The experimental design has 28 experiments that include 24 main runs and four replicate in center point. The optimal conditions obtained from the selective acidic leaching experiments, were sulfuric acid concentration of 1 pct v/v, leaching temperature of 343 K (70 °C), pulp density of 8 pct w/v, and stirring speed of 300 rpm. The results show that the zinc and manganese recoveries after staged selective leaching are about 92 and 15 pct, respectively. Finally, metallic zinc with purity of 99.9 pct and electrolytic manganese dioxide were obtained by electrowinning.

NLEAP/GIS approach for identifying and mitigating regional nitrate-nitrogen leaching

USGS Publications Warehouse

Shaffer, M.J.; Hall, M.D.; Wylie, B.K.; Wagner, D.G.; Corwin, D.L.; Loague, K.

1996-01-01

Improved simulation-based methodology is needed to help identify broad geographical areas where potential NO3-N leaching may be occurring from agriculture and suggest management alternatives that minimize the problem. The Nitrate Leaching and Economic Analysis Package (NLEAP) model was applied to estimate regional NO3-N leaching in eastern Colorado. Results show that a combined NLEAP/GIS technology can be used to identify potential NO3-N hot spots in shallow alluvial aquifers under irrigated agriculture. The NLEAP NO3-N Leached (NL) index provided the most promising single index followed by NO3-N Available for Leaching (NAL). The same combined technology also shows promise in identifying Best Management Practice (BMP) methods that help minimize NO3-N leaching in vulnerable areas. Future plans call for linkage of the NLEAP/GIS procedures with groundwater modeling to establish a mechanistic analysis of agriculture-aquifer interactions at a regional scale.

The Neurological Basis and Potential Modification of Emotional Intelligence through Affective/Behavioral Training

DTIC Science & Technology

2010-10-01

facial trustworthiness; facial displays of anger) presented subliminally . Furthermore, the responsiveness of these regions to subliminal stimulation ...develop, or program the computerized stimulation paradigms for use during functional neuroimaging (i.e., MJT; BMAT; EFAT). These paradigms will be...programming began on the computerized functional MRI stimulation paradigms using e-prime software. • Quarter #2: Programming of all computerized functional

DOE Zero Energy Ready Home Case Study: Palo Duro Homes — Palo Duro Homes, Albuquerque, NM

DOE Office of Scientific and Technical Information (OSTI.GOV)

none,

2014-09-01

This builder was honored for Most DOE Zero Energy Ready Homes Built in the 2014 Housing Innovation Awards. By July 2014, Palo Duro had completed 152 homes since the program began in 2013 (under the original program title DOE Challenge Home), all of them certified to the stringent efficiency requirements of DOE’s Zero Energy Ready Home program.

Big Programs from a Small State: Less Commonly Taught Languages Find Their Home in Delaware Elementary Schools

ERIC Educational Resources Information Center

Fulkerson, Gregory

2009-01-01

This article describes three big programs from Delaware where the less commonly taught languages find their home in Delaware elementary schools. Odyssey Charter School, located in Wilmington, is one of the very few Greek-language-focused public schools in the nation. The school began in 2006 as a Greek immersion program that concentrated on the…

Educating Copacabana: A Critical Analysis of the "Second Half", an Olympic Education Program of Rio 2016

ERIC Educational Resources Information Center

Knijnik, Jorge; Tavares, Otavio

2012-01-01

The Second Half Program (SHP) is an educational sports program running in Brazil. It began in 2003 and was one of the Olympic educational proposals described in the Rio 2016 Olympics bid. Using sport as a tool, the SHP aims to deliver moral education and to promote citizenship in order to counteract "social exclusion" and "social…

The United States National Library Power School Program: Research Evaluation and Implications for Professional Development and Library Education.

ERIC Educational Resources Information Center

Hopkins, Dianne McAfee; Zweizig, Douglas L.

The Library Power program is a school improvement initiative of the DeWitt-Wallace Reader's Digest Fund that began in 1988, designed to promote the full integration of the school library media program into the school curriculum in public elementary and junior high/middle schools. With a total investment exceeding $45 million, Library Power is the…

The Satellites, Weather and Climate (SWAC) Teacher Professional Development Program: Making the Case for Climate and Geospatial Literacy

ERIC Educational Resources Information Center

Dupigny-Giroux, Lesley-Ann; Toolin, Regina; Hogan, Stephen; Fortney, Michael D.

2012-01-01

In July 2008, a new professional development program called Satellites, Weather and Climate (SWAC) began at the University of Vermont. Its goal was to enhance the competency of in-service K-12 science and mathematics Vermont teachers in the atmospheric, climate, and geospatial sciences. The pilot program ran until 2010, during which time 14…

CHIP Utilization in South Texas: A Prospective Longitudinal Study of the Children's Health Insurance Program. JSRI Research Report No. 33

ERIC Educational Resources Information Center

Millard, Ann V.; Mier, Nelda; Gabriel, Olga; Flores, Soledad

2004-01-01

The Children's Health Insurance Program (CHIP) began as a federal stopgap measure to assist families whose incomes were too high to qualify for Medicaid, but too low to make health insurance for their children affordable. In 2002, efforts were launched around the United States to recruit eligible children into the program. This pilot study…

The Evolution of WebCT in a Baccalaureate Nursing Program: An Alice in Wonderland Reflection

ERIC Educational Resources Information Center

Donato, Emily; Hudyma, Shirlene; Carter, Lorraine; Schroeder, Catherine

2010-01-01

The use of WebCT in the Laurentian University Bachelor of Science in Nursing program began in 2001 when faculty were eager to explore different modes of delivery for fourth-year courses. Since then, the use of WebCT within the baccalaureate program has increased substantively. This paper outlines the developmental growth of the use of this…

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

The Department of Energy's Strategic Petroleum Reserve Program began leaching the Bryan Mound salt dome and discharging brine into the coastal waters offshore of Freeport, Texas on March 10, 1980. This report describes the findings of a team of Texas A and M University scientists and engineers who have conducted a study to evaluate the effects of the Bryan Mound brine discharge on the marine environment. The study addresses the areas of physical oceanography, analysis of the discharge plume, water and sediment quality, nekton, benthos and data management. It focuses on the period from September 1982 through August 1983. Themore » ambient physical environment and its temporal and spatial variability were studied by means of continuously recording in situ current/conductivitiy/temperature meters and twelve, one-day synoptic hydrographic cruises. The quarterly water and sediment quality data show a small increase in salinity, sodium and chloride ions occurs in the bottom waters and sediment pore waters near the diffuser relative to those values measured at stations farther away. Data from the brine plume study for this reporting study show the largest areal extent within the +1 o/oo above ambient salinity contour was 40.0 km/sup 2/ which occurred on August 11, 1983. It appears that brine disposal at Bryan Mound has had neglible if any influence on the nekton community surrounding the diffuser. The benthic quarterly data from 26 stations, including 7 collections made after the diffuser outflow rate was increased to 1,000,000 barrels/day, show the total numbers of species at the diffuser station were higher than most other nearfield stations as well as many farfield stations in both the pre- and post-1,000,000 barrels/day brine flow periods. 138 references, 175 figures, 53 tables.« less

Lead in drinking water and human blood lead levels in the United States.

PubMed

Brown, Mary Jean; Margolis, Stephen

2012-08-10

Lead is a pervasive environmental contaminant. The adverse health effects of lead exposure in children and adults are well documented, and no safe blood lead threshold in children has been identified. Lead can be ingested from various sources, including lead paint and house dust contaminated by lead paint, as well as soil, drinking water, and food. The concentration of lead, total amount of lead consumed, and duration of lead exposure influence the severity of health effects. Because lead accumulates in the body, all sources of lead should be controlled or eliminated to prevent childhood lead poisoning. Beginning in the 1970s, lead concentrations in air, tap water, food, dust, and soil began to be substantially reduced, resulting in significantly reduced blood lead levels (BLLs) in children throughout the United States. However, children are still being exposed to lead, and many of these children live in housing built before the 1978 ban on lead-based residential paint. These homes might contain lead paint hazards, as well as drinking water service lines made from lead, lead solder, or plumbing materials that contain lead. Adequate corrosion control reduces the leaching of lead plumbing components or solder into drinking water. The majority of public water utilities are in compliance with the Safe Drinking Water Act Lead and Copper Rule (LCR) of 1991. However, some children are still exposed to lead in drinking water. EPA is reviewing LCR, and additional changes to the rule are expected that will further protect public health. Childhood lead poisoning prevention programs should be made aware of the results of local public water system lead monitoring measurement under LCR and consider drinking water as a potential cause of increased BLLs, especially when other sources of lead exposure are not identified.

INFLUENCE OF PH AND REDOX CONDITIONS ON COPPER LEACHING

EPA Science Inventory

Leaching behavior of metals from a mineral processing waste at varying pH and redox conditions was studies. Effect of combinations of pH and Eh on leaching of copper is described. Leaching of copper was found to be dependent on both pH and Eh. Higher concentrations of Cu were ...

Study on mechanisms of different sulfuric acid leaching technologies of chromite

NASA Astrophysics Data System (ADS)

Shi, Pei-yang; Liu, Cheng-jun; Zhao, Qing; Shi, Hao-nan

2017-09-01

The extraction of chromate from chromite via the sulfuric acid leaching process has strong potential for practical use because it is a simple and environmentally friendly process. This paper aims to study the sulfuric acid leaching process using chromite as a raw material via either microwave irradiation or in the presence of an oxidizing agent. The results show that the main phases in Pakistan chromite are ferrichromspinel, chrompicotite, hortonolite, and silicate embedded around the spinel phases. Compared with the process with an oxidizing agent, the process involving microwaves has a higher leaching efficiency. When the mass fraction of sulfuric acid was 80% and the leaching time was 20 min, the efficiency could exceed 85%. In addition, the mechanisms of these two technologies fundamentally differ. When the leaching was processed in the presence of an oxidizing agent, the silicate was leached first and then expanded. By contrast, in the case of leaching under microwave irradiation, the chromite was dissolved layer by layer and numerous cracks appeared at the particle surface because of thermal shock. In addition, the silicate phase shrunk instead of expanding.

Nitrate leaching in a winter wheat-summer maize rotation on a calcareous soil as affected by nitrogen and straw management

PubMed Central

Huang, Tao; Ju, Xiaotang; Yang, Hao

2017-01-01

Nitrate leaching is one of the most important pathways of nitrogen (N) loss which leads to groundwater contamination or surface water eutrophication. Clarifying the rates, controlling factors and characteristics of nitrate leaching is the pre-requisite for proposing effective mitigation strategies. We investigated the effects of interactions among chemical N fertilizer, straw and manure applications on nitrogen leaching in an intensively managed calcareous Fluvo-aquic soil with winter wheat-summer maize cropping rotations on the North China Plain from October 2010 to September 2013 using ceramic suction cups and seepage water calculations based on a long-term field experiment. Annual nitrate leaching reached 38–60 kg N ha−1 from conventional N managements, but declined by 32–71% due to optimum N, compost manure or municipal waste treatments, respectively. Nitrate leaching concentrated in the summer maize season, and fewer leaching events with high amounts are the characteristics of nitrate leaching in this region. Overuse of chemical N fertilizers, high net mineralization and nitrification, together with predominance of rainfall in the summer season with light soil texture are the main controlling factors responsible for the high nitrate leaching loss in this soil-crop-climatic system. PMID:28176865

Leaching behavior and chemical stability of copper butyl xanthate complex under acidic conditions.

PubMed

Chang, Yi Kuo; Chang, Juu En; Chiang, Li Choung

2003-08-01

Although xanthate addition can be used for treating copper-containing wastewater, a better understanding of the leaching toxicity and the stability characteristics of the copper xanthate complexes formed is essential. This work was undertaken to evaluate the leaching behavior of copper xanthate complex precipitates by means of toxicity characteristics leaching procedure (TCLP) and semi-dynamic leaching test (SDLT) using 1 N acetic acid solution as the leachant. Also, the chemical stability of the copper xanthate complex during extraction has been examined with the studying of variation of chemical structure using UV-vis, Fourier transform infrared and X-ray photoelectron spectroscopies (XPS). Both TCLP and SDLT results showed that a negligible amount of copper ion was leached out from the copper xanthate complex precipitate, indicating that the complex exhibited a high degree of copper leaching stability under acidic conditions. Nevertheless, chemical structure of the copper xanthate complex precipitate varied during the leaching tests. XPS data suggested that the copper xanthate complex initially contained both cupric and cuprous xanthate, but the unstable cupric xanthate change to the cuprous form after acid extraction, indicating the cuprous xanthate to be the final stabilizing structure. Despite that, the changes of chemical structure did not induce the rapid leaching of copper from the copper xanthate complex.

Release of heavy metals during long-term land application of sewage sludge compost: Percolation leaching tests with repeated additions of compost.

PubMed

Fang, Wen; Delapp, Rossane C; Kosson, David S; van der Sloot, Hans A; Liu, Jianguo

2017-02-01

Leaching assessment procedures have been used to determine the leachability of heavy metals as input for evaluating the risk from sewage sludge compost land application. However, relatively little attention has been paid to understanding leaching from soils with repeated application of sewage sludge compost with elevated levels of heavy metals. In this paper, leaching assessment is extended to evaluate the potential leaching of heavy metals during repetitive application of composted sewage sludge to soils. Four cycling of compost additions and percolation leaching were conducted to investigate how leaching behavior of heavy metals changed with repeated additions of compost. Results showed that repetitive additions of compost to soil significantly increased the content of organic matter, which favored the formation of reducing condition due to improved microbial activities and oxygen consumption. Establishment of reducing conditions can enhance the leaching concentrations of As by approximately 1 order of magnitude, especially for the soil rich in organic matter. For Cd, Cr, Cu, and Pb, repeated additions of compost will cause accumulation in total contents but not enhancement in leaching concentrations. The infiltration following compost additions will leach out the mobile fraction and the residual fraction might not release in the next cycling of compost addition and infiltration. The cumulative release of Cd, Cr, Cu, and Pb accounted for less than 5% of the total contents during four times of compost applications. Copyright © 2016 Elsevier Ltd. All rights reserved.

Leaching composted lignocellulosic wastes to prepare container media: feasibility and environmental concerns.

PubMed

Fornes, Fernando; Carrión, Carolina; García-de-la-Fuente, Rosana; Puchades, Rosa; Abad, Manuel

2010-08-01

The leaching of salt and mineral elements from three composts prepared with residual vegetable crop biomass (melon, pepper or zucchini) was studied using methacrylate columns and distilled water. The benefits of the leached composts to be used for ornamental potted plant production were also analysed. After leaching 5 container capacities of effluent, both the electrical conductivity and the concentration of soluble mineral elements in compost leachates decreased substantially and remained close to the target levels. Composts reacted differently to leaching due to differences in the raw waste sources and the composting process and hence, in their physical and chemical characteristics. At the end of the experiment, after pouring 8 container capacities of water, the leaching efficiency of the salts was 96%, 93% and 87% for melon, pepper and zucchini-based composts, respectively. Mineral elements differed in their ability to be removed from the composts; N (NH(4)(+) and NO(3)(-)), K(+), Na(+), Cl(-), and SO(4)(2-) were leached readily, whereas H(2)PO(4)(-), Ca(2+), and Mg(2+) were removed hardly. Leached composts showed a range of physico-chemical and chemical characteristics suitable for use as growing media constituents. Potted Calendula and Calceolaria plants grew in the substrates prepared with the leached composts better than in those made with the non-leached ones. Finally, special emphasis must be paid to the management of the effluents produced under commercial conditions to avoid environmental pollution. Copyright 2010 Elsevier Ltd. All rights reserved.

Identifying a rainfall event threshold triggering herbicide leaching by preferential flow

NASA Astrophysics Data System (ADS)

McGrath, G. S.; Hinz, C.; Sivapalan, M.; Dressel, J.; Pütz, T.; Vereecken, H.

2010-02-01

How can leaching risk be assessed if the chemical flux and/or the toxicity is highly uncertain? For many strongly sorbing pesticides it is known that their transport through the unsaturated zone occurs intermittently through preferential flow, triggered by significant rainfall events. In these circumstances the timing and frequency of these rainfall events may allow quantification of leaching risk to overcome the limitations of flux prediction. In this paper we analyze the leaching behavior of bromide and two herbicides, methabenzthiazuron and ethidimuron, using data from twelve uncropped lysimeters, with high-resolution climate data, in order to identify the rainfall controls on rapid solute leaching. A regression tree analysis suggested that a coarse-scale fortnightly to monthly water balance was a good predictor of short-term increases in drainage and bromide transport. Significant short-term herbicide leaching, however, was better predicted by the occurrence of a single storm with a depth greater than a 19 mm threshold. Sampling periods where rain events exceeded this threshold accounted for between 38% and 56% of the total mass of herbicides leached during the experiment. The same threshold only accounted for between 1% and 10% of the total mass of bromide leached. On the basis of these results, we conclude that in this system, the leaching risks of strongly sorbing chemicals can be quantified by the timing and frequency of these large rainfall events. Empirical and modeling approaches are suggested to apply this frequentist approach to leaching risk assessment to other soil-climate systems.

Valorization of GaN based metal-organic chemical vapor deposition dust a semiconductor power device industry waste through mechanochemical oxidation and leaching: A sustainable green process.

PubMed

Swain, Basudev; Mishra, Chinmayee; Lee, Chan Gi; Park, Kyung-Soo; Lee, Kun-Jae

2015-07-01

Dust generated during metal organic vapor deposition (MOCVD) process of GaN based semiconductor power device industry contains significant amounts of gallium and indium. These semiconductor power device industry wastes contain gallium as GaN and Ga0.97N0.9O0.09 is a concern for the environment which can add value through recycling. In the present study, this waste is recycled through mechanochemical oxidation and leaching. For quantitative recovery of gallium, two different mechanochemical oxidation leaching process flow sheets are proposed. In one process, first the Ga0.97N0.9O0.09 of the MOCVD dust is leached at the optimum condition. Subsequently, the leach residue is mechanochemically treated, followed by oxidative annealing and finally re-leached. In the second process, the MOCVD waste dust is mechanochemically treated, followed by oxidative annealing and finally leached. Both of these treatment processes are competitive with each other, appropriate for gallium leaching and treatment of the waste MOCVD dust. Without mechanochemical oxidation, 40.11 and 1.86 w/w% of gallium and Indium are leached using 4M HCl, 100°C and pulp density of 100 kg/m(3,) respectively. After mechanochemical oxidation, both these processes achieved 90 w/w% of gallium and 1.86 w/w% of indium leaching at their optimum condition. Copyright © 2015 Elsevier Inc. All rights reserved.

Leaching of lead from computer printed wire boards and cathode ray tubes by municipal solid waste landfill leachates.

PubMed

Jang, Yong-Chul; Townsend, Timothy G

2003-10-15

The proper management of discarded electronic devices (E-waste) is an important issue for solid waste professionals because of the magnitude of the waste stream and because these devices often contain a variety of toxic metals (e.g., lead). While recycling of E-waste is developing, much of this waste stream is disposed in landfills. Leaching tests are frequently used to characterize the potential of a solid waste to leach when disposed in a landfill. In the United States, the Toxicity Characteristic Leaching Procedure (TCLP) is used to determine whether a solid waste is a hazardous waste by the toxicity characteristic. The TCLP is designed to simulate worse-case leaching in a landfill environment where the waste is co-disposed with municipal solid waste (MSW). While the TCLP is a required analysis from a regulatory perspective, the leachate concentrations measured may not accurately reflect the concentrations observed under typical landfill conditions. Another method that can be performed to assess the degree a pollutant might leach from a waste in a landfill is to use actual landfill leachate as the leaching solution. In this study, two lead-containing components found in electronic devices (printed wire boards from computers and cathode ray tubes from computers and televisions) were leached using the TCLP and leachates from 11 Florida landfills. California's Waste Extraction Test (WET) and the Synthetic Precipitation Leaching Procedure were also performed. The results indicated that the extractions using MSW landfill leachates resulted in lower lead concentrations than those by the TCLP. The pH of the leaching solution and the ability of the organic acids in the TCLP and WET to complex with the lead are factors that regulate the amount of lead leached.

Effect of Harsh or Mild Extraction of Soil on Pesticide Leaching to Groundwater.

PubMed

Boesten, Jos J T I

2016-07-01

Assessment of leaching to groundwater is an important aspect of pesticide risk assessment. The first leaching tier usually consists of simulations with leaching scenarios based on pesticide-soil properties derived from laboratory studies. Because the extractability of pesticide residues in such studies decreases with time, the harshness of the extraction method influences these pesticide-soil properties. This study investigates the effect of using a mild or harsh extraction method on simulated leaching to groundwater with consideration of substances with a range of half-lives and organic matter sorption coefficient values for selected leaching scenarios. The model for linking the concentrations of the mild and the harsh systems was based on laboratory studies with two pesticides and a Dutch sandy soil and was tested against Canadian field studies with atrazine (6-chloro-2-ethyl-4-isopropyl-1,3,5-triazine-2,4-diamine). The degradation rate and the aged-sorption parameters of each "mild" soil-substance system were derived from a hypothetical laboratory incubation study using prescribed parameter values for the corresponding "harsh" soil-substance system. Simulations were performed for three European leaching scenarios (United Kingdom, France, Portugal). For the best-guess parameter set, the leaching concentrations of the harsh system were approximately equal to those of the mild system at leaching concentrations greater than 1 μg L and were at most approximately a factor of two higher than those of the mild systems at mild leaching concentrations between 0.01 and 0.1 μg L. However, an extreme parameter set led to harsh leaching concentrations that were at most approximately 10 times higher than the mild leaching concentrations at levels between 0.01 and 0.1 μg L. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Observing phthalate leaching from plasticized polymer films at the molecular level.

PubMed

Zhang, Xiaoxian; Chen, Zhan

2014-05-06

Phthalates, the most widely used plasticizers in poly(vinyl chloride) (PVC), have been extensively studied. In this paper, a highly sensitive, easy, and effective method was developed to examine short-term phthalate leaching from PVC/phthalate films at the molecular level using sum frequency generation vibrational spectroscopy (SFG). Combining SFG and Fourier transform infrared spectroscopy (FTIR), surface and bulk molecular structures of PVC/phthalate films were also comprehensively evaluated during the phthalate leaching process under various environments. The leaching processes of two phthalates, diethyl phthalate (DEP) and dibutyl phthalate (DBP), from the PVC/phthalate films with various weight ratios were studied. Oxygen plasma was applied to treat the PVC/phthalate film surfaces to verify its efficacy on preventing/reducing phthalate leaching from PVC. Our results show that DBP is more stable than DEP in PVC/phthalate films. Even so, DBP molecules were still found to very slowly leach to the environment from PVC at 30 °C, at a rate much slower than DEP. Also, the bulk DBP content substantially influences the DBP leaching. Higher DBP bulk concentration yields less stable DBP molecules in the PVC matrix, allowing molecules to leach from the polymer film more easily. Additionally, DBP leaching is very sensitive to temperature changes; higher temperature can strongly enhance the leaching process. For most cases, the oxygen plasma treatment can effectively prevent phthalate leaching from PVC films (e.g., for samples with low bulk concentrations of DBP-5 and 30 wt %). It is also capable of reducing phthalate leaching from high DBP bulk concentration PVC samples (e.g., 70 wt % DBP in PVC/DBP mixture). This research develops a highly sensitive method to detect chemicals at the molecular level as well as provides surface and bulk molecular structural changes. The method developed here is general and can be applied to detect small amounts of chemical/biological environmental contaminants.

The pH-dependent leaching behavior of slags from various stages of a copper smelting process: Environmental implications.

PubMed

Jarošíková, Alice; Ettler, Vojtěch; Mihaljevič, Martin; Kříbek, Bohdan; Mapani, Ben

2017-02-01

The leaching behaviors of primary copper (Cu) slags originating from Ausmelt, reverbatory, and converter furnaces operating under a single technological process were compared to a residual slag tailing obtained by slag re-processing via flotation and metal recovery. The EN 12457-2 leaching test, used for assessment of the hazardous properties, was followed by the CEN/TS 14997 pH-static leaching test (pH range 3-12). Both leaching experiments were coupled with a mineralogical investigation of the primary and secondary phases as well as geochemical modeling. Metals (Cd, Cu, Pb, Zn) exhibit the highest leaching at low pH. Under acidic conditions (pH 3-6), Ausmelt slag and slag tailing exhibited higher metal leaching compared to other slag types. Very low leaching of metals (far below EU limits for non-hazardous waste) was observed at natural pH (7.9-9.0) for all the studied slag samples. In contrast, relatively high leaching of As was observed over the entire pH range, especially for Ausmelt slag (exceeding the EU limit for hazardous waste by 1.7×). However, geochemical modeling and scanning electron microscopy indicated that formation of stable Ca-Cu-Pb arsenates and the binding of As to newly formed Fe (oxyhydr)oxides play an important role in efficient As immobilization at the slag-water interface. In contrast, no controls were predicted for Sb, whose leaching was almost pH-independent. Nevertheless Sb leached concentrations at natural pH were below EU limit for hazardous waste. Re-processing of primary Cu slags for metal recovery, and subsequent co-disposal of the resulting slag tailing with dolomite-rich mine tailing and local laterite is suitable for stabilizing the remaining contaminants (except Sb) and limiting their leaching into the environment. Copyright © 2016 Elsevier Ltd. All rights reserved.

Sequential Leaching of Chromium Contaminated Sediments - A Study Characterizing Natural Attenuation

NASA Astrophysics Data System (ADS)

Musa, D.; Ding, M.; Beroff, S.; Rearick, M.; Perkins, G.; WoldeGabriel, G. W.; Ware, D.; Harris, R.; Kluk, E.; Katzman, D.; Reimus, P. W.; Heikoop, J. M.

2015-12-01

Natural attenuation is an important process in slowing down the transport of hexavalent chromium, Cr(VI), an anthropogenic environmental contaminant, either by adsorption of Cr(VI) to sediments, or by reduction to nontoxic trivalent chromium, Cr(III). The capacity and mechanism of attenuation is explored in this sequential leaching study of different particle size fractions of chromium contaminated sediments and similar uncontaminated sediments from the regional aquifer near Los Alamos, New Mexico. Using this leaching protocol each sediment sample is split in two: one half is leached three times using a 0.1 M sodium bicarbonate/carbonate solution, while the second half is leached three times using a 0.01 M nitric acid, followed by two consecutively increasing magnitudes of nitric acid concentrations. Based on the amphoteric nature of chromium, alkaline leaching is used to establish the amount of Cr(VI) sorbed on the sediment, whereas acid leaching is used to establish the amount of Cr(III). The weak acid is predicted to release the attenuated anthropogenic Cr(III), without affecting Cr-bearing minerals. The sequential, stronger, acid is anticipated to leach Cr(III)-incorporated in the minerals. The efficiency and validation of the sequential leaching method is assessed by comparing the leaching behavior of bentonite and biotite samples, with and without loaded Cr(VI). A 97% chromium mass balance of leached Cr(VI)-loaded bentonite and biotite proves the viability of this method for further use on leaching contaminated sediments. By comparing contaminated and uncontaminated sediment leachate results, of chromium and other major and trace elements, the signature of anthropogenic chromium is determined. Further mineralogical characterization of the sediments provides a quantitative measure of the natural attenuation capacity for chromium. Understanding these results is pertinent in delineating the optimal procedure for the remediation of Cr(VI) in the regional aquifer near Los Alamos.

Arsenic Speciation of Solvent-Extracted Leachate from New and Weathered CCA-Treated Wood

PubMed Central

KHAN, BERNINE I.; SOLO - GABRIELE, HELENA M.; DUBEY, BRAJESH K.; TOWNSEND, TIMOTHY G.; CAI, YONG

2009-01-01

For the past 60 yr, chromate-copper-arsenate (CCA) has been used to pressure-treat millions of cubic meters of wood in the United States for the construction of many outdoor structures. Leaching of arsenic from these structures is a possible health concern as there exists the potential for soil and groundwater contamination. While previous studies have focused on total arsenic concentrations leaching from CCA-treated wood, information pertaining to the speciation of arsenic leached is limited. Since arsenic toxicity is dependent upon speciation, the objective of this study was to identify and quantify arsenic species leaching from new and weathered CCA-treated wood and CCA-treated wood ash. Solvent-extraction experiments were carried out by subjecting the treated wood and the ash to solvents of varying pH values, solvents defined in the EPA’s Synthetic Precipitation Leaching Procedure (SPLP) and Toxicity Characteristic Leaching Procedure (TCLP), rainwater, deionized water, and seawater. The generated leachates were analyzed for inorganic As(III) and As(V) and the organoarsenic species, monomethylarsonic acid (MMAA) and dimethylarsinic acid (DMAA), using high-performance liquid chromatography followed by hydride generation and atomic fluorescence spectrometry (HPLC–HG-AFS). Only the inorganic species were detected in any of the wood leachates; no organoarsenic species were found. Inorganic As(V) was the major detectable species leaching from both new and weathered wood. The weathered wood leached relatively more overall arsenic and was attributed to increased inorganic As(III) leaching. The greater presence of As(III) in the weathered wood samples as compared to the new wood samples may be due to natural chemical and biological transformations during the weathering process. CCA-treated wood ash leached more arsenic than unburned wood using the SPLP and TCLP, and ash samples leached more inorganic As(III) than the unburned counterparts. Increased leaching was due to higher concentrations of arsenic within the ash and to the conversion of some As(V) to As(III) during combustion. PMID:15461159

Leaching characteristics of toxic constituents from coal fly ash mixed soils under the influence of pH

DOE Office of Scientific and Technical Information (OSTI.GOV)

Komonweeraket, Kanokwan; Cetin, Bora, E-mail: bora.cetin@sdsmt.edu; Benson, Craig H., E-mail: chbenson@wisc.edu

Highlights: • The impact of pH on the leaching of elements and metals from fly ash mixed soils. • Generally Ca, Cd, Mg, and Sr follows a cationic leaching pattern. • The leaching of As and Se shows an oxyanionic leaching pattern. • The leaching behavior of elements does not change based on material type. • Different fly ash types show different abilities in immobilizing trace elements. - Abstract: Leaching behaviors of Arsenic (As), Barium (Ba), Calcium (Ca), Cadmium (Cd), Magnesium (Mg), Selenium (Se), and Strontium (Sr) from soil alone, coal fly ash alone, and soil-coal fly ash mixtures, weremore » studied at a pH range of 2–14 via pH-dependent leaching tests. Seven different types of soils and coal fly ashes were tested. Results of this study indicated that Ca, Cd, Mg, and Sr showed cationic leaching pattern while As and Se generally follows an oxyanionic leaching pattern. On the other hand, leaching of Ba presented amphoteric-like leaching pattern but less pH-dependent. In spite of different types and composition of soil and coal fly ash investigated, the study reveals the similarity in leaching behavior as a function of pH for a given element from soil, coal fly ash, and soil-coal fly ash mixtures. The similarity is most likely due to similar controlling mechanisms (e.g., solubility, sorption, and solid-solution formation) and similar controlling factors (e.g., leachate pH and redox conditions). This offers the opportunity to transfer knowledge of coal fly ash that has been extensively characterized and studied to soil stabilized with coal fly ash. It is speculated that unburned carbon in off-specification coal fly ashes may provide sorption sites for Cd resulting in a reduction in concentration of these elements in leachate from soil-coal fly ash mixture. Class C fly ash provides sufficient CaO to initiate the pozzolanic reaction yielding hydrated cement products that oxyanions, including As and Se, can be incorporated into.« less

PEP Support Laboratory Leaching and Permeate Stability Tests

DOE Office of Scientific and Technical Information (OSTI.GOV)

Russell, Renee L.; Peterson, Reid A.; Rinehart, Donald E.

2009-09-25

Pacific Northwest National Laboratory (PNNL) has been tasked by Bechtel National Inc. (BNI) on the River Protection Project-Hanford Tank Waste Treatment and Immobilization Plant (RPP-WTP) project to perform research and development activities to resolve technical issues identified for the Pretreatment Facility (PTF). The Pretreatment Engineering Platform (PEP) was designed, constructed, and operated as part of a plan to respond to issue M12, "Undemonstrated Leaching Processes," of the External Flowsheet Review Team (EFRT) issue response plan.( ) The PEP is a 1/4.5-scale test platform designed to simulate the WTP pretreatment caustic leaching, oxidative leaching, ultrafiltration solids concentration, and slurry washing processes.more » The PEP replicates the WTP leaching processes using prototypic equipment and control strategies. A simplified flow diagram of the PEP system is shown in Figure 1.1. Two operating scenarios are currently being evaluated for the ultrafiltration process (UFP) and leaching operations. The first scenario has caustic leaching performed in the UFP-2 ultrafiltration feed vessels (i.e., vessel UFP-VSL-T02A in the PEP and vessels UFP-VSL-00002A and B in the WTP PTF). The second scenario has caustic leaching conducted in the UFP-1 ultrafiltration feed preparation vessels (i.e., vessels UFP-VSL-T01A and B in the PEP and vessels UFP-VSL-00001A and B in the WTP PTF). In both scenarios, 19-M sodium hydroxide solution (NaOH, caustic) is added to the waste slurry in the vessels to leach solid aluminum compounds (e.g., gibbsite, boehmite). Caustic addition is followed by a heating step that uses direct injection of steam to accelerate the leach process. Following the caustic leach, the vessel contents are cooled using vessel cooling jackets and/or external heat exchangers. The main difference between the two scenarios is that for leaching in UFP-VSL-T01A and B, the 19-M NaOH is added to un-concentrated waste slurry (3 to 8 wt% solids), while for leaching in UFP-VSL-T02A, the slurry is concentrated to nominally 20 wt% solids using cross-flow ultrafiltration before adding caustic.« less

Applications analysis report: Silicate Technology Corporation's solidification/stabilization technology for organic and inorganic contaminants in soils

NASA Astrophysics Data System (ADS)

Bates, E.

1992-12-01

The STC demonstration was conducted under EPA's Superfund Innovative Technology Evaluation (SITE) Program in November, 1990, at the Selma Pressure Treating (SPT) wood preserving site in Selma, California. The SPT site was contaminated with both organics, predominantly pentachlorophenol (PCP), inorganics, mainly arsenic, chromium, and copper. Extensive sampling and analyses were performed on the waste both before and after treatment to compare physical, chemical, and leaching characteristics of raw and treated wastes. STC's contaminated soil treatment process was evaluated based on contaminant mobility measured by numerous leaching tests, structural integrity of the solidified material, measured by physical and engineering tests and morphological examinations; and economic analysis, using cost information supplied by STC and the results of the SITE demonstration, the vendor's design and test data, and other laboratory and field applications of the technology. It discusses the advantages, disadvantages, and limitations, as well as estimated costs of the technology.

Historically Black Colleges and Universities Nuclear Energy Training Program: Summary of program activities, fiscal year 1986

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1987-04-27

The Historically Black Colleges and Universities Nuclear Energy Training (HBCU NET) Program, funded by DOE, Office of Nuclear Energy and administered by ORAU, began in February 1984. The program provides support for training, study, research participation, and academic enrichment of students and faculty at designated HBCUs in nuclear science, nuclear engineering, and other nuclear-related technologes and disciplines. The program is composed of undergraduate scholarships, graduate fellowships, student and faculty research participation, and an annual student training institute.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Josephson, Gary B.; Geeting, John GH; Bredt, Ofelia P.

Pacific Northwest National Laboratory (PNNL) has been tasked by Bechtel National Inc. (BNI) on the River Protection Project-Waste Treatment Plant (RPP-WTP) project to perform research and development activities to resolve technical issues identified for the Pretreatment Facility (PTF). The Pretreatment Engineering Platform (PEP) was designed, constructed, and operated as part of a plan to respond to issue M12, "Undemonstrated Leaching Processes." The PEP is a 1/4.5-scale test platform designed to simulate the WTP pretreatment caustic leaching, oxidative leaching, ultrafiltration solids concentration, and slurry washing processes. The PEP replicates the WTP leaching processes using prototypic equipment and control strategies. The PEPmore » also includes non-prototypic ancillary equipment to support the core processing. Two operating scenarios are currently being evaluated for the ultrafiltration process (UFP) and leaching operations. The first scenario has caustic leaching performed in the UFP-2 ultrafiltration feed vessels (i.e., vessel UFP-VSL-T02A in the PEP; and vessels UFP-VSL-00002A and B in the WTP PTF). The second scenario has caustic leaching conducted in the UFP-1 ultrafiltration feed preparation vessels (i.e., vessels UFP-VSL-T01A and B in the PEP; vessels UFP-VSL-00001A and B in the WTP PTF). In both scenarios, 19-M sodium hydroxide solution (NaOH, caustic) is added to the waste slurry in the vessels to leach solid aluminum compounds (e.g., gibbsite, boehmite). Caustic addition is followed by a heating step that uses direct injection of steam to accelerate the leach process. Following the caustic leach, the vessel contents are cooled using vessel cooling jackets and/or external heat exchangers. The main difference between the two scenarios is that for leaching in UFP-1, the 19-M NaOH is added to un-concentrated waste slurry (3-8 wt% solids), while for leaching in UFP-2, the slurry is concentrated to nominally 20 wt% solids using cross-flow ultrafiltration before the addition of caustic. In both scenarios, following the caustic leach, the slurry was then concentrated to 17 wt% and washed with inhibited water to remove NaOH and other soluble salts. Next, the slurry was oxidatively leached using sodium permanganate to solubilize chrome. The slurry was then washed to remove the dissolved chrome and concentrated.« less

Bilingual Occupational Education--Adult. Evaluation Report.

ERIC Educational Resources Information Center

Rochester City School District, NY.

The overall objective of the program was to provide 200 Spanish-speaking adults and out-of-school youth, 16 years of age or older, with occupational instruction and English language skills which would enhance the enrollees' opportunities to acquire entry level job skills or upgrade the enrollees' present occupational status. The program began with…

Impact of WOWW's Fine Arts Enriched Education Programming

ERIC Educational Resources Information Center

Sharp, Laurie A.; Tiegs, Ali

2018-01-01

Learning through the fine arts possesses many benefits, yet efforts to address the arts within public schools, particularly rural schools, are insufficient. In an effort to support rural public schools in Texas, Window On a Wider World (WOWW) began providing fine arts enriched education programming in 2006 to area partner schools that serve…

Quality and Efficiency in a Complementary Middle School Program: The "Educatodos" Experience in Honduras

ERIC Educational Resources Information Center

Marshall, Jeffery H.; Mejia R., Marco Tulio; Aguilar, Claudia R.

2008-01-01

In this article, the authors use recently collected data from the "Educatodos" program in Honduras to analyze attrition, an outcome that has received little attention in previous analyses of alternative school effectiveness. "Educatodos" began in the 1990s with radio courses in primary grades mainly for rural adults. Through…

Another Perspective: El Sistema--A Perspective for North American Music Educators

ERIC Educational Resources Information Center

Tunstall, Tricia

2013-01-01

Herein, Tricia Tunstall presents a critique of the article by Melissa Lesniak published in the December 2012 "Music Educators Journal," and offers a new perspective on the Venezuelan youth orchestra program known as "El Sistema." The program, which began in Caracas thirty-eight years ago, is dedicated to changing the lives of…

The Healthy Homes Partnership: A Cooperative Extension Model

ERIC Educational Resources Information Center

Booth, Laura B.; Peek, Gina G.

2013-01-01

This article highlights the accomplishments of the Healthy Homes Partnership, which recently celebrated its 10th anniversary. Since the program began in 1999, funds totaling $2.7 million have been distributed to 34 states and Virgin Islands Extension programs through a competitive process. Extension professionals have used the funds as seed grants…

Annual Performance Report. 2002-2003. Wyoming Department of Education.

ERIC Educational Resources Information Center

Wyoming State Department of Education, 2004

2004-01-01

Wyoming's Department of Education (WDE?s) Special Programs Unit conducts compliance monitoring for all IDEA procedural requirements on a five-year cycle. The current process began for Wyoming?s school districts in 1999-2000 and will be completed in 2004-05. The special education monitoring process is a comprehensive program review. The process…

Salem Program Demonstrates Five Keys to a Successful Business--School Partnership.

ERIC Educational Resources Information Center

Jensen, Mary Cihak

1985-01-01

Partnerships between schools and businesses are becoming more frequent and more reciprocal as the two find common interests; the Salem-Keizer (Oregon) Public Schools provide a nationally recognized example of such a partnership. Salem's program began in 1981 with a joint school board and Chamber of Commerce policy statement. Despite economic…

Healthe Kids: An Assessment of Program Performance and Participation

ERIC Educational Resources Information Center

Dean, Bonnie B.; Kindermann, Sylvia L.; Carson, Tabetha; Gavin, Jan; Frerking, Melissa; Bergren, Martha Dewey

2014-01-01

Many states in the United States have mandated school health screenings for early identification and referral to professional services for a set of health conditions. Healthe Kids, a community-based program, began offering school-based health screenings to Missouri elementary schools in March 2007. The purpose of the article is to provide a…

Profiles of Adult Learners.

ERIC Educational Resources Information Center

Illinois State Library, Springfield.

Since January 1986, when the Illinois Secretary of State Literacy Grant Program began funding a wide variety of adult literacy programs, more than 30,000 students have sought help with reading. They have been matched with 25,000 tutors who have provided more than 2 million hours of volunteer instruction. The profiles in this booklet are stories of…

Retraining Displaced Workers: The US Experience. Training Policy Study No. 1.

ERIC Educational Resources Information Center

Leigh, Duane E.

The federal government's experience with adult retraining programs began in 1962 with the passage of the Manpower Development and Training Act and creation of the Trade Adjustment Assistance program. When the 1973 Comprehensive Employment and Training Act expired in 1982, Congress enacted the Job Training Partnership Act. During the 1980s, states…

Private Voucher and Scholarship Plans. Trends and Issues.

ERIC Educational Resources Information Center

Hadderman, Margaret

This article examines an increasingly popular alternative to government-funded voucher plans: private voucher and scholarship plans. Through the 1998-99 school year, spending on privately funded voucher programs totalled $61 million. Private vouchers began with the Golden Rule Program in Indianapolis in 1991 and was inspired by insurance CEO J.…

Science Shorts: Project BudBurst--Analyzing Data

ERIC Educational Resources Information Center

Davis, Kimberly J.; Coskie, Tracy L.

2008-01-01

Project BudBurst is a national program intended to get students and other "citizen scientists" to participate in a real study about plants, the environment, and climate change. It also provides an excellent opportunity for students to build data-analysis skills. A collaboration of several agencies and universities, the program began last year and…

Reducing Lead in School Drinking Water: A Case Study.

ERIC Educational Resources Information Center

Odell, Lee

1991-01-01

The Seattle School District began a program in 1990 to identify lead levels in the district's drinking water and to implement measures to lower any high lead levels. Recounts each of the seven steps of the program, discusses what the district found, and explains how it lowered lead levels in the drinking water. (MLF)

National Aeronautics and Space Administration (NASA) Education 1993-2009

ERIC Educational Resources Information Center

Ivie, Christine M.

2009-01-01

The National Aeronautics and Space Administration was established in 1958 and began operating a formal education program in 1993. The purpose of this study was to analyze the education program from 1993-2009 by examining strategic plan documents produced by the NASA education office and interviewing NASA education officials who served during that…

Development of Competency Based Credential Programs in Southern California's High Desert Region.

ERIC Educational Resources Information Center

Burton, Louise F.; And Others

In the northern high desert region of San Bernardino County (California), about half of special education teachers do not hold special education credentials. In September 1988, the Desert-Mountain Rural Training Program began to provide appropriate training to uncredentialed special education teachers in this sparsely populated area. The program…

Impact of Government Shutdown on Child Care and Early Education Programs

ERIC Educational Resources Information Center

Center for Law and Social Policy, Inc. (CLASP), 2013

2013-01-01

Congress did not enact a continuing resolution bill by midnight September 30, 2013, thereby triggering a partial government shutdown effective October 1, 2013. October 1 began the federal fiscal year 2014. Most discretionary programs, those that are subject to the annual Congressional appropriations process, will not receive 2014 funding. Most,…

Television for Children in Japan: Trends and Studies.

ERIC Educational Resources Information Center

Kodaira, Sachiko Imaizumi

In Japan, the production and broadcasting of television (TV) programs for children began in 1953. After the first few years of trial and error, children's programs gradually rose in popularity with the introduction of TV animation, dramas, special-effects photography, music/variety and quiz shows, comedies, and action dramas. Since the inception…

Computer Programming with Early Elementary Students with Down Syndrome

ERIC Educational Resources Information Center

Taylor, Matthew S.; Vasquez, Eleazar; Donehower, Claire

2017-01-01

Students of all ages and abilities must be given the opportunity to learn academic skills that can shape future opportunities and careers. Researchers in the mid-1970s and 1980s began teaching young students the processes of computer programming using basic coding skills and limited technology. As technology became more personalized and easily…

Leading Your School to Excellence through Reading Instruction

ERIC Educational Resources Information Center

James, Salethia R.

2014-01-01

After decades of attempting to identify effective reading programs within the United States, in recent years, the emphasis on identifying these programs has made a dramatic shift. The continuous increase in federal involvement began the implementation of No Child Left Behind (NCLB). One of the primary goals for NCLB is to drastically improve…

Critical Success Factors: PVCC Teacher Education Transfers to the University of Virginia.

ERIC Educational Resources Information Center

Wilson, Eleanor Vernon

This report examines the collaborative program between Piedmont Virginia Community College (PVCC) and the Curry School of Education at the University of Virginia (UVA). The program began in 1997 and was designed to encourage PVCC students, particularly minority and other nontraditional students, to participate in the Introduction to Teaching…

Wave of the Future?: Integrating IR, Outcomes Assessment, Planning, Program Review, and Accreditation

ERIC Educational Resources Information Center

Leimer, Christina

2010-01-01

Integrating institutional research, outcomes assessment, program review, strategic planning, and accreditation can be a powerful means of creating a culture of evidence-based decision making and continuous improvement. This study examined how this "integrated" model is organized in practice, how such offices began, why this approach was chosen,…

Student Activities Programs: Their Status and the Impact of the Reform Movement.

ERIC Educational Resources Information Center

Vornberg, James A.

Research studies have consistently indicated that participation in school activities benefits both students and schools. Since the school reform movement began in 1983, the importance of school activities and student time commitment to such programs are increasingly being scrutinized. This paper summarizes a study to determine: (1) the current…

The Full-Time School Program in Mexico

ERIC Educational Resources Information Center

Zermeño, Marcela Georgina Gómez; Fahara, Manuel Flores; de la Garza, Lorena Alemán

2014-01-01

The Full-time Schools Program in Mexico ("Programa Escuelas de Tiempo Completo," PETC), began in the 2007-2008 school year with the aim of improving the learning opportunities of basic education students by extending the school day to eight hours a day, in order to offer an innovative and flexible pedagogical proposal that includes six…

Council for Unity, Inc. 1993-94.

ERIC Educational Resources Information Center

Schearer, Mary

The Council for Unity began in 1975 in response to repeated incidents of interracial violence in a New York City high school. The program's primary goal has been to promote intergroup awareness, sensitivity, and cooperation among groups from diverse ethnic, racial, and religious groups and to reduce bias. The program currently operates in 15 high…

Silver Alerts and the Problem of Missing Adults with Dementia

ERIC Educational Resources Information Center

Carr, Dawn; Muschert, Glenn W.; Kinney, Jennifer; Robbins, Emily; Petonito, Gina; Manning, Lydia; Brown, J. Scott

2010-01-01

In the months following the introduction of the National AMBER (America's Missing: Broadcast Emergency Response) Alert plan used to locate missing and abducted children, Silver Alert programs began to emerge. These programs use the same infrastructure and approach to find a different missing population, cognitively impaired older adults. By late…

American Sign Language-English Interpreting Program Faculty: Characteristics, Tenure Perceptions, and Productivity

ERIC Educational Resources Information Center

Hale, Kimberly J.

2012-01-01

American Sign Language (ASL)-English interpreting education, which began as a community apprenticeship and vetting process, has within the last several decades moved into higher education. Most recently, the number of baccalaureate-granting ASL-English interpreting programs have continued to increase while the number of associate's degree…

The Hispanic Project for Architecture and Building Construction

ERIC Educational Resources Information Center

Dail, Edward; Mora, Jorge

2006-01-01

John Tyler Community College in Chester, Virginia, began a program in architecture and building construction in fall 2003 to meet the needs of the Hispanic community--a much neglected but rapidly growing segment of the regional population. After first hiring a Hispanic director (Mr. Jorge Mora), a program was developed that heavily involved the…

U.S. Information Ambassadors: The 1991-92 Library Fellows and Debriefing Report.

ERIC Educational Resources Information Center

Doyle, Robert P.

The American Library Association (ALA) Library Fellows program began in 1986 with a grant from the U.S. Information Agency. The program's purpose is threefold: (1) to increase international understanding through the establishment of professional and personal relationships and the accomplishment of mutual goals; (2) to promote international sharing…

The Methodist University Sustainable Program: Using the Earth Charter to Mainstream Sustainability

ERIC Educational Resources Information Center

Matarazzo-Neuberger, Waverli Maia; Filho, Vicente Manzione

2010-01-01

This article describes a pioneering initiative of a Brazilian university to introduce sustainability in all undergraduate curricula and in its operations. The Methodist University Sustainable Program was developed in a bottom-up way and began with the introduction of sustainability as a core value in the Institutional Political-Pedagogical Plan,…

An Exploration into Learner Experiences with Mandated Learning Portfolios in Graduate Medical Education

ERIC Educational Resources Information Center

Mulligan, Margaret H.

2009-01-01

In 1999, the Accreditation Council of Graduate Medical Education (ACGME) began the Outcome Project which re-focused program accreditation decisions. Six competency areas detailed new standards, calling for programs to measure and provide evidence of learner's acquisition of the knowledge and skills for independent practice in a specific specialty.…

Texas' Project RIO (Re-Integration of Offenders): Program Focus.

ERIC Educational Resources Information Center

Finn, Peter

Texas's Project RIO (Re-Integration of Offenders), which was developed in cooperation with the National Institute of Justice, National Institute of Corrections, and U.S. Department of Education's Office of Correctional Education, began in 1985 as a two-city pilot program to place parolees in jobs. Project RIO has since expanded steadily and now…

EFRT M12 Issue Resolution: Comparison of PEP and Bench-Scale Oxidative Leaching Results

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rapko, Brian M.; Brown, Christopher F.; Eslinger, Paul W.

2009-08-14

Pacific Northwest National Laboratory (PNNL) has been tasked by Bechtel National Inc. (BNI) on the River Protection Project-Hanford Tank Waste Treatment and Immobilization Plant (RPP-WTP) project to perform research and development activities to resolve technical issues identified for the Pretreatment Facility (PTF). The Pretreatment Engineering Platform (PEP) was designed and constructed and is to be operated as part of a plan to respond to issue M12, “Undemonstrated Leaching Processes.” The PEP is a 1/4.5-scale test platform designed to simulate the WTP pretreatment caustic leaching, oxidative leaching, ultrafiltration solids concentration, and slurry washing processes. The PEP replicates the WTP leaching processesmore » using prototypic equipment and control strategies. The PEP also includes non-prototypic ancillary equipment to support the core processing. Two operating scenarios are currently being evaluated for the ultrafiltration process (UFP) and leaching operations. The first scenario has caustic leaching performed in the UFP-2 ultrafiltration feed vessels (i.e., vessel UFP-VSL-T02A in the PEP; and vessels UFP-VSL-00002A and B in the WTP PTF). The second scenario has caustic leaching conducted in the UFP-1 ultrafiltration feed preparation vessels (i.e., vessels UFP-VSL-T01A and B in the PEP; vessels UFP-VSL-00001A and B in the WTP PTF). In both scenarios, 19-M sodium hydroxide solution (NaOH, caustic) is added to the waste slurry in the vessels to dissolve solid aluminum compounds (e.g., gibbsite, boehmite). Caustic addition is followed by a heating step that uses direct steam injection to accelerate the leaching process. Following the caustic leach, the vessel contents are cooled using vessel cooling jackets and/or external heat exchangers. The main difference between the two scenarios is that for leaching in UFP1, the 19-M NaOH is added to un-concentrated waste slurry (3 to 8 wt% solids), while for leaching in UFP2, the slurry is concentrated to nominally 20 wt% solids using cross-flow ultrafiltration before the addition of caustic. For wastes that have significantly high chromium content, the caustic leaching and slurry dewatering is followed by adding sodium permanganate to UFP-VSL-T02A, and the slurry is subjected to oxidative leaching at nominally ambient temperature. The purpose of the oxidative leaching is to selectively oxidize the poorly alkaline-soluble Cr(III) believed to be the insoluble form in Hanford tank sludge to the much more alkaline-soluble Cr(VI), e.g., chromate. The work described in this report provides the test results that are related to the efficiency of the oxidative leaching process to support process modeling based on tests performed with a Hanford waste simulant. The tests were completed both at the lab-bench scale and in the PEP. The purpose of this report is to summarize the results from both scales that are related to oxidative leaching chemistry to support a scale factor for the submodels to be used in the G2 model, which predicts WTP operating performance. Owing to schedule constraints, the PEP test data to be included in this report are limited to those from Integrated Tests A (T01 A/B caustic leaching) and B (T02A caustic leaching).« less

25 CFR 171.305 - Will BIA provide leaching service to me?

Code of Federal Regulations, 2010 CFR

2010-04-01

... 25 Indians 1 2010-04-01 2010-04-01 false Will BIA provide leaching service to me? 171.305 Section... OPERATION AND MAINTENANCE Water Use § 171.305 Will BIA provide leaching service to me? (a) We may provide you leaching service if: (1) You submit a written plan that documents how soil salinity limits your...

25 CFR 171.305 - Will BIA provide leaching service to me?

Code of Federal Regulations, 2014 CFR

2014-04-01

... 25 Indians 1 2014-04-01 2014-04-01 false Will BIA provide leaching service to me? 171.305 Section... OPERATION AND MAINTENANCE Water Use § 171.305 Will BIA provide leaching service to me? (a) We may provide you leaching service if: (1) You submit a written plan that documents how soil salinity limits your...

Chapter 14: Evaluating the Leaching of Biocides from Preservative-Treated Wood Products

Treesearch

Stan T. Lebow

2014-01-01

Leaching of biocides is an important consideration in the long term durability and any potential for environmental impact of treated wood products. This chapter discusses factors affecting biocide leaching, as well as methods of evaluating rate and quantity of biocide released. The extent of leaching is a function of preservative formulation, treatment methods, wood...

Technical Note: Comparison of accelerated methods for evaluating leaching from preservative-treated wood

Treesearch

Stan T. Lebow; Patricia K. Lebow; Kolby C. Hirth

2017-01-01

Current standardized methods are not well-suited for estimating in-service preservative leaching from treated wood products. This study compared several alternative leaching methods to a commonly used standard method, and to leaching under natural exposure conditions. Small blocks or lumber specimens were pressure treated with a wood preservative containing borax and...

Studies on leaching from spruce twigs and beech leaves.

PubMed

Fritsche, U

1992-01-01

Leaching, depending on the acidity of the eluent, was investigated for K, Mg and Mn. The curves for the leachate concentration versus time could be described by a power function. Leaching from old needles exceeded leaching from young needles to a high degree, but the ratios of the leached elements were almost equal. A method for continuous measurements of pH change in solutions contacting plant materials was developed. The results were in agreement with data on acidity changes in water falling through spruce or beech canopies.

PROCESS FOR RECOVERY OF URANIUM AND VANADIUM FROM CARBONATE SOLUTIONS BY REDUCTION-PRECIPITATION

DOEpatents

Ellis, D.A.; Lindblom, R.O.

1957-09-24

A process employing carbonate leaching of ores and an advantageous methcd of recovering the uranium and vanadium from the leach solution is described. The uranium and vanadium can be precipitated from carbonate leach solutions by reaction with sodium amalgam leaving the leach solution in such a condition that it is economical to replenish for recycling. Such a carbonate leach solution is treated with a dilute sodium amalgam having a sodium concentration within a range of about 0.01 to 0.5% of sodium. Efficiency of the treatment is dependent on at least three additional factors, intimacy of contact of the amalgam with the leach solution, rate of addition of the amalgam and exclusion of oxygen (air).

Orbital express capture system: concept to reality

NASA Astrophysics Data System (ADS)

Stamm, Shane; Motaghedi, Pejmun

2004-08-01

The development of autonomous servicing of on-orbit spacecraft has been a sought after objective for many years. A critical component of on-orbit servicing involves the ability to successfully capture, institute mate, and perform electrical and fluid transfers autonomously. As part of a Small Business Innovation Research (SBIR) grant, Starsys Research Corporation (SRC) began developing such a system. Phase I of the grant started in 1999, with initial work focusing on simultaneously defining the parameters associated with successful docking while designing to those parameters. Despite the challenge of working without specific requirements, SRC completed development of a prototype design in 2000. Throughout the following year, testing was conducted on the prototype to characterize its performance. Having successfully completed work on the prototype, SRC began a Phase II SBIR effort in mid-2001. The focus of the second phase was a commercialization effort designed to augment the prototype model into a more flight-like design. The technical requirements, however, still needed clear definition for the design to progress. The advent of the Orbital Express (OE) program provided much of that definition. While still in the proposal stages of the OE program, SRC began tailoring prototype redesign efforts to the OE program requirements. A primary challenge involved striking a balance between addressing the technical requirements of OE while designing within the scope of the SBIR. Upon award of the OE contract, the Phase II SBIR design has been fully developed. This new design, designated the Mechanical Docking System (MDS), successfully incorporated many of the requirements of the OE program. SRC is now completing dynamic testing on the MDS hardware, with a parallel effort of developing a flight design for OE. As testing on the MDS progresses, the design path that was once common to both SBIR effort and the OE program begins to diverge. The MDS will complete the scope of the Phase II SBIR work, while the new mechanism, the Orbital Express Capture System, will emerge as a flight-qualified design for the Orbital Express program.

Mercury, Skylab, Spacehab, International Space Station: A Continuum

NASA Technical Reports Server (NTRS)

Walker, Charles; Crouch, Roger K.; Binnenbruck, Horsta; Nagaoka, Shunji; Riesselmann, Werner

2000-01-01

We have conducted real research in space. Virtually all that we conducted in the first decade and a half of the space age was government funded and basic research like the carrier vehicles we call satellites and Sputniki, but direction human interaction began with Project Mercury. When the Apollo program ended with success, we got back to research again. Skylab was using Apollo hardware, using Apollo systems in a manner that offered spacious accomodations for researchers. Education began to move into space. This document describes Skylab's role in spaceborne experiments.

Sustainable recovery of valuable metals from spent lithium-ion batteries using DL-malic acid: Leaching and kinetics aspect.

PubMed

Sun, Conghao; Xu, Liping; Chen, Xiangping; Qiu, Tianyun; Zhou, Tao

2018-02-01

An eco-friendly and benign process has been investigated for the dissolution of Li, Co, Ni, and Mn from the cathode materials of spent LiNi 1/3 Co 1/3 Mn 1/3 O 2 batteries, using DL-malic acid as the leaching agent in this study. The leaching efficiencies of Li, Co, Ni, and Mn can reach about 98.9%, 94.3%, 95.1%, and 96.4%, respectively, under the leaching conditions of DL-malic acid concentration of 1.2 M, hydrogen peroxide content of 1.5 vol.%, solid-to-liquid ratio of 40 g l -1 , leaching temperature of 80°C, and leaching time of 30 min. In addition, the leaching kinetic was investigated based on the shrinking model and the results reveal that the leaching reaction is controlled by chemical reactions within 10 min with activation energies (Ea) of 21.3 kJ·mol -1 , 30.4 kJ·mol -1 , 27.9 kJ·mol -1 , and 26.2 kJ·mol -1 for Li, Co, Ni, and Mn, respectively. Diffusion process becomes the controlled step with a prolonged leaching time from 15 to 30 min, and the activation energies (Ea) are 20.2 kJ·mol -1 , 28.9 kJ·mol -1 , 26.3 kJ·mol -1 , and 25.0 kJ·mol -1 for Li, Co, Ni, and Mn, respectively. This hydrometallurgical route was found to be effective and environmentally friendly for leaching metals from spent lithium batteries.

A sustainable process for the recovery of valuable metals from spent lithium-ion batteries.

PubMed

Fan, Bailin; Chen, Xiangping; Zhou, Tao; Zhang, Jinxia; Xu, Bao

2016-05-01

In this work, an eco-friendly and hydrometallurgical process for the recovery of cobalt and lithium from spent lithium-ion batteries has been proposed, which includes pretreatment, citric acid leaching, selective chemical precipitation and circulatory leaching. After pretreatment (manual dismantling, N-methyl pyrrolidone immersion and calcination), Cu and Al foils are recycled directly and the cathode active materials are separated from the cathode efficiently. Then, the obtained cathode active materials (waste LiCoO2) was firstly leached with 1.25 mol l(-1) citric acid and 1 vol.% H2O2 solution. Then cobalt was precipitated using oxalic acid (H2C2O4) under a molar ratio of 1:1.05 (H2C2O4: Co(2+)). After filtration, the filtrate (containing Li(+)) and H2O2 was employed as a leaching agent and the optimum conditions are studied in detail. The leaching efficiencies can reach as high as 98% for Li and 90.2% for Co, respectively, using filter liquor as leaching reagent under conditions of leaching temperature of 90°C, 0.9 vol.% H2O2 and a solid-to-liquid ratio of 60 ml g(-1) for 35 min. After three bouts of circulatory leaching, more than 90% Li and 80% Co can be leached under the same leaching conditions. In this way, Li and Co can be recovered efficiently and waste liquor re-utilization is achievable with this hydrometallurgical process, which may promise both economic and environmental benefits. © The Author(s) 2016.

Thermal treatment of stabilized air pollution control residues in a waste incinerator pilot plant. Part 2: Leaching characteristics of bottom ashes.

PubMed

Baun, Dorthe L; Christensen, Thomas H; Bergfeldt, Brita; Vehlow, Jürgen; Mogensen, Erhardt P B

2004-02-01

With the perspective of generating only one solid residue from waste incineration, co-feeding of municipal solid waste and air pollution control residues stabilized by the Ferrox process was investigated in the TAMARA pilot plant incinerator as described in Bergfeldt et al. (Waste Management Research, 22, 49-57, 2004). This paper reports on leaching from the combined bottom ashes. Batch leaching test, pH-static leaching tests, availability tests and column leaching tests were used to characterize the leaching properties. The leaching properties are key information in the context of reuse in construction or in landfilling of the combined residue. In general, the combined bottom ashes had leaching characteristics similar to the reference bottom ash, which contained no APC residue. However, As and Pb showed slightly elevated leaching from the combined bottom ashes, while Cr showed less leaching. The investigated combined bottom ashes had contents of metals comparable to what is expected at steady state after continuous co-feeding of APC residues. Only Cd and Pb were partly volatilized (30-40%) during the incineration process and thus the combined bottom ashes had lower contents of Cd and Pb than expected at steady state. Furthermore, a major loss of Hg was, not surprisingly, seen and co-feeding of Ferrox-products together with municipal solid waste will require dedicated removal of Hg in the flue gas to prevent a build up of Hg in the system. In spite of this, a combined single solid residue from waste incineration seems to be a significant environmental improvement to current technology.

Leaching from solid waste incineration ashes used in cement-treated base layers for pavements.

PubMed

Cai, Z; Bager, Dirch H; Christensen, T H

2004-01-01

Waste incineration bottom ash and treated flue gas cleaning products mixed with 2.5% of cement (50 kg/m3) were tested in the laboratory in terms of compressive strength and tank leaching tests over a 64-day period. Although the material displayed lower mechanical strength than a reference concrete, the strength still was sufficient for use as a base layer for roads. The metal content in the incineration-residue-based specimens was up to 100 times higher than in the reference concrete, suggesting that the mixed waste incineration residue should be used only for dedicated purposes. The leaching of Cl and Na was increased by a factor of 20-100 from the incineration-residue-based specimens as compared to the reference, while the leaching of K, Ca and SO4 was increased by a factor of 2-10. The leaching of heavy metals was also higher from the incineration-residue-based specimens than from the reference with respect to Cu (50 times), Cd, Pb and Zn (5 times), but not with respect to Cr and Ni. The leaching curves did only allow for a closer evaluation of the leaching process in a few cases. The physical retention of the constituents seemed to be the same in the reference as in the incineration-residue-based specimens. Heavy metal leaching was limited by enhanced chemical retention in the incineration-residue-specimens as compared to the reference. Since no quality criteria in terms of leaching from a monolithic material are currently available, the leaching issue must be evaluated case by case.

Maximum availability and mineralogical control of chromium released from AOD slag.

PubMed

Li, Junguo; Liu, Bao; Zeng, Yanan; Wang, Ziming; Gao, Zhiyuan

2017-03-01

AOD (argon oxygen decarburization) slag is the by-product in the stainless steel refining process. Chromium existing in AOD slag can leach out and probably poses a serious threat to the environment. To assess the leaching toxicity of chromium released from AOD slag, the temperature-dependent maximum availability leaching test was performed. To determine the controlling mineralogical phases of chromium released from AOD slag, a Visual MINTEQ simulation was established based on Vminteq30 and the FactSage 7.0 database. The leaching tests indicated that the leaching availability of chromium was slight and mainly consisted of trivalent chromium. Aging of AOD slag under the atmosphere can oxidize trivalent chromium to hexavalent chromium, which could be leached out by rainwater. According to the simulation, the chromium concentration in leachates was controlled by the freely soluble pseudo-binary phases in the pH = 7.0 leaching process and controlled by the Cr 2 O 3 phase in the pH = 4.0 leaching process. Chromium concentrations were underestimated when the controlling phases were determined to be FeCr 2 O 4 and MgCr 2 O 4 . Facilitating the generation of the insoluble spinel-like phases during the cooling and disposal process of the molten slag could be an effective approach to decreasing the leaching concentration of chromium and its environmental risk.

Selective recovery of gold from waste mobile phone PCBs by hydrometallurgical process.

PubMed

Kim, Eun-young; Kim, Min-seuk; Lee, Jae-chun; Pandey, B D

2011-12-30

The leaching of gold from the scrap mobile phone PCBs by electro-generated chlorine as an oxidant and its recovery by ion exchange process was investigated. The leaching experiments were carried out by employing separate leaching reactor connected with the anode compartment of a Cl(2) gas generator. The leaching of gold increased with increase in temperature and initial concentration of chlorine, and was favorable even at low concentration of acid, whereas copper leaching increased with increase in concentration of acid and decrease in temperature. In a two-stage leaching process, copper was mostly dissolved (97%) in 165 min at 25°C during the 1st stage leaching in 2.0 mol/L HCl by electro-generated chlorine at a current density of 714A/m(2) along with a minor recovery of gold (5%). In the 2nd stage gold was mostly leached out (93% recovery, ∼67 mg/L) from the residue of the 1st stage by the electro-generated chlorine in 0.1 mol/L HCl. Gold recovery from the leach liquor by ion exchange using Amberlite XAD-7HP resin was found to be 95% with the maximum amount of gold adsorbed as 46.03 mg/g resin. A concentrated gold solution, 6034 mg/L with 99.9% purity was obtained in the ion exchange process. Copyright © 2011 Elsevier B.V. All rights reserved.

Rare earth element recycling from waste nickel-metal hydride batteries.

PubMed

Yang, Xiuli; Zhang, Junwei; Fang, Xihui

2014-08-30

With an increase in number of waste nickel-metal hydride batteries, and because of the importance of rare earth elements, the recycling of rare earth elements is becoming increasingly important. In this paper, we investigate the effects of temperature, hydrochloric acid concentration, and leaching time to optimize leaching conditions and determine leach kinetics. The results indicate that an increase in temperature, hydrochloric acid concentration, and leaching time enhance the leaching rate of rare earth elements. A maximum rare earth elements recovery of 95.16% was achieved at optimal leaching conditions of 70°C, solid/liquid ratio of 1:10, 20% hydrochloric acid concentration, -74μm particle size, and 100min leaching time. The experimental data were best fitted by a chemical reaction-controlled model. The activation energy was 43.98kJ/mol and the reaction order for hydrochloric acid concentration was 0.64. The kinetic equation for the leaching process was found to be: 1-(1-x)(1/3)=A/ρr0[HCl](0.64)exp-439,8008.314Tt. After leaching and filtration, by adding saturated oxalic solution to the filtrate, rare earth element oxalates were obtained. After removing impurities by adding ammonia, filtering, washing with dilute hydrochloric acid, and calcining at 810°C, a final product of 99% pure rare earth oxides was obtained. Copyright © 2014 Elsevier B.V. All rights reserved.

Site-specific critical acid load estimates for forest soils in the Osborn Creek watershed, Michigan

Treesearch

Trevor Hobbs; Jason Lynch; Randy Kolka

2017-01-01

Anthropogenic acid deposition has the potential to accelerate leaching of soil cations, and in turn, deplete nutrients essential to forest vegetation. The critical load concept, employing a simple mass balance (SMB) approach, is often used to model this process. In an evaluation under the U.S. Forest Service Watershed Condition Framework program, soils in all 6th level...

Multistage leaching of metals from spent lithium ion battery waste using electrochemically generated acidic lixiviant.

PubMed

Boxall, N J; Adamek, N; Cheng, K Y; Haque, N; Bruckard, W; Kaksonen, A H

2018-04-01

Lithium ion battery (LIB) waste contains significant valuable resources that could be recovered and reused to manufacture new products. This study aimed to develop an alternative process for extracting metals from LIB waste using acidic solutions generated by electrolysis for leaching. Results showed that solutions generated by electrolysis of 0.5 M NaCl at 8 V with graphite or mixed metal oxide (MMO) electrodes were weakly acidic and leach yields obtained under single stage (batch) leaching were poor (<10%). This was due to the highly acid-consuming nature of the battery waste. Multistage leaching with the graphite electrolyte solution improved leach yields overall, but the electrodes corroded over time. Though yields obtained with both electrolyte leach solutions were low when compared to the 4 M HCl control, there still remains potential to optimise the conditions for the generation of the acidic anolyte solution and the solubilisation of valuable metals from the LIB waste. A preliminary value proposition indicated that the process has the potential to be economically feasible if leach yields can be improved, especially based on the value of recoverable cobalt and lithium. Copyright © 2018 Elsevier Ltd. All rights reserved.

A comparison of ultrasound-augmented and conventional leaching of silver from sintering dust using acidic thiourea.

PubMed

Chang, Jun; Zhang, Er-Dong; Zhang, Li-Bo; Peng, Jin-Hui; Zhou, Jun-Wen; Srinivasakannan, C; Yang, Chang-Jiang

2017-01-01

In the process of steel manufacture, up to ten millions of tons of sintering dust (SD) are produced annually in China, which contain noble metals such as Ag. Therefore, recovery of silver (Ag) from SD could be a potential economic and environmental activity. The purpose of this article is to generate information about reaction kinetics of silver leaching with thiourea from SD, comparing the conventional and ultrasonic-augment leaching. The effects of various control parameters such as the ultrasound power, particle size, leaching temperature and thiourea concentration on leaching rate of silver were studied. The results showed 89% silver recovery for conventional process against 95% for ultrasound assisted leaching. The ultrasonic wave increased the leaching rate and shorten the reaction time. The rate controlling step was analyzed using shrinking core model and the rate controlling step is identified to be the diffusion through the product layer in both conventional and ultrasonic-augment leaching processes. The activation energies were estimated to be 28.01kJ/mol and 18.19kJ/mol, and the reaction order were 0.89 and 0.71, respectively. Copyright © 2016 Elsevier B.V. All rights reserved.

Evaluation of six pesticides leaching indexes using field data of herbicide application in Casablanca Valley, Chile.

PubMed

Kogan, M; Rojas, S; Gómez, P; Suárez, F; Muñoz, J F; Alister, C

2007-01-01

A field study was performed to evaluate the accuracy of six pesticide screening leaching indexes for herbicide movement. Adsorption, dissipation and soil movement were studied in a vineyard in a sandy loam soil during 2005 season. Simazine, diuron, pendimethalin, oxyfluorfen and flumioxazin were applied to bare soil at rates commonly used, and their soil concentrations throughout soil profile were determined at 0, 10, 20, 40 and 90 days after application (DAA). Herbicides were subjected to two pluviometric regimens, natural field condition and modified conditions (plus natural rainfall 180 mm). Leaching indexes utilized were: Briggs's Rf, Hamaker's Rf, LEACH, LPI, GUS and LIX. Simazine reached 120 cm, diuron 90 cm, flumioxazin 30 cm soil depth respectively. Pendimethalin and oxyfluorfen were retained up to 5 cm. None of the herbicides leaching was affected by rainfall regimen. Only flumioxazin field dissipation was clearly affected by pluviometric condition. The best representation of the herbicide soil depth movement and leaching below 15 cm soil depth were: Hamaker's Rf < Briggs's Rf < GUS < LPI, < LEACH < LIX. Field results showed a good correlation between herbicides K(d) and their soil depth movement and mass leached below 15 cm soil depth.

Co-treatment of spent cathode carbon in caustic and acid leaching process under ultrasonic assisted for preparation of SiC.

PubMed

Yuan, Jie; Xiao, Jin; Li, Fachuang; Wang, Bingjie; Yao, Zhen; Yu, Bailie; Zhang, Liuyun

2018-03-01

Spent cathode carbon (SCC) from aluminum electrolysis has been treated in ultrasonic-assisted caustic leaching and acid leaching process, and purified SCC used as carbon source to synthesize silicon carbide (SiC) was investigated. Chemical and mineralogical properties have been characterized by X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM), and thermogravimetry and differential scanning calorimetry (TGA-DSC). Various experimental factors temperature, time, liquid-solid ratio, ultrasonic power, and initial concentration of alkali or acid affecting on SCC leaching result were studied. After co-treatment with ultrasonic-assisted caustic leaching and acid leaching, carbon content of leaching residue was 97.53%. SiC power was synthesized by carbothermal reduction at 1600 °C, as a result of yield of 76.43%, and specific surface area of 4378 cm 2 /g. This is the first report of using purified SCC and gangue to prepare SiC. The two industrial wastes have been used newly as secondary sources. Furthermore, ultrasonic showed significant effect in SCC leaching process. Copyright © 2017 Elsevier B.V. All rights reserved.

Optimization of reaction conditions for the electroleaching of manganese from low-grade pyrolusite

NASA Astrophysics Data System (ADS)

Zhang, Xing-ran; Liu, Zuo-hua; Fan, Xing; Lian, Xin; Tao, Chang-yuan

2015-11-01

In the present study, a response surface methodology was used to optimize the electroleaching of Mn from low-grade pyrolusite. Ferrous sulfate heptahydrate was used in this reaction as a reducing agent in sulfuric acid solutions. The effect of six process variables, including the mass ratio of ferrous sulfate heptahydrate to pyrolusite, mass ratio of sulfuric acid to pyrolusite, liquid-to-solid ratio, current density, leaching temperature, and leaching time, as well as their binary interactions, were modeled. The results revealed that the order of these factors with respect to their effects on the leaching efficiency were mass ratio of ferrous sulfate heptahydrate to pyrolusite > leaching time > mass ratio of sulfuric acid to pyrolusite > liquid-to-solid ratio > leaching temperature > current density. The optimum conditions were as follows: 1.10:1 mass ratio of ferrous sulfate heptahydrate to pyrolusite, 0.9:1 mass ratio of sulfuric acid to pyrolusite, liquid-to-solid ratio of 0.7:1, current density of 947 A/m2, leaching time of 180 min, and leaching temperature of 73°C. Under these conditions, the predicted leaching efficiency for Mn was 94.1%; the obtained experimental result was 95.7%, which confirmed the validity of the model.

Removal of hazardous metals from MSW fly ash--an evaluation of ash leaching methods.

PubMed

Fedje, Karin Karlfeldt; Ekberg, Christian; Skarnemark, Gunnar; Steenari, Britt-Marie

2010-01-15

Incineration is a commonly applied management method for municipal solid waste (MSW). However, significant amounts of potentially hazardous metal species are present in the resulting ash, and these may be leached into the environment. A common idea for cleaning the ash is to use enhanced leaching with strong mineral acids. However, due to the alkalinity of the ash, large amounts of acid are needed and this is a drawback. Therefore, this work was undertaken in order to investigate some alternative leaching media (EDTA, ammonium nitrate, ammonium chloride and a number of organic acids) and to compare them with the usual mineral acids and water. All leaching methods gave a significant increase in ash specific surface area due to removal of soluble bulk (matrix) compounds, such as CaCO(3) and alkali metal chlorides. The use of mineral acids and EDTA mobilised many elements, especially Cu, Zn and Pb, whereas the organic acids generally were not very effective as leaching agents for metals. Leaching using NH(4)NO(3) was especially effective for the release of Cu. The results show that washing of MSW filter ash with alternative leaching agents is a possible way to remove hazardous metals from MSW fly ash.

Environmental Compliance Assessment Management Program (ECAMP) - U.S. Fish and Wildlife Service (FWS)

DTIC Science & Technology

1994-06-01

and Wildlife Service, began research on the Environmental Compliance Assessment and Management Program (ECAMP). The concept was to combine Code of ... The number of environmental laws and regulations have continued to grow in the United States and worldwide, making compliance with these regulations...Service has adopted an environmental compliance program that identifies compliance problems before they are cited as violations by the U.S

The Important Bird Areas Program in the United States: building a network of sites for conservation, state by state

Treesearch

Jeffrey V. Wells; Daniel K. Niven; John Cecil

2005-01-01

The Important Bird Area (IBA) program is an international effort to identify, conserve, and monitor a network of sites that provide essential habitat for bird populations. BirdLife International began the IBA program in Europe in 1985. Since that time, BirdLife partners in more than 100 countries have joined together to build the global IBA network. Audubon (BirdLife...

Counter-current acid leaching process for copper azole treated wood waste.

PubMed

Janin, Amélie; Riche, Pauline; Blais, Jean-François; Mercier, Guy; Cooper, Paul; Morris, Paul

2012-09-01

This study explores the performance of a counter-current leaching process (CCLP) for copper extraction from copper azole treated wood waste for recycling of wood and copper. The leaching process uses three acid leaching steps with 0.1 M H2SO4 at 75degrees C and 15% slurry density followed by three rinses with water. Copper is recovered from the leachate using electrodeposition at 5 amperes (A) for 75 min. Ten counter-current remediation cycles were completed achieving > or = 94% copper extraction from the wood during the 10 cycles; 80-90% of the copper was recovered from the extract solution by electrodeposition. The counter-current leaching process reduced acid consumption by 86% and effluent discharge volume was 12 times lower compared with the same process without use of counter-current leaching. However, the reuse of leachates from one leaching step to another released dissolved organic carbon and caused its build-up in the early cycles.

Extraction of Vanadium from Vanadium Slag Via Non-salt Roasting and Ammonium Oxalate Leaching

NASA Astrophysics Data System (ADS)

Li, Meng; Du, Hao; Zheng, Shili; Wang, Shaona; Zhang, Yang; Liu, Biao; Dreisinger, David Bruce; Zhang, Yi

2017-10-01

A clean method featuring non-salt roasting followed by (NH4)2C2O4 leaching to recover vanadium from vanadium slag was proposed. The carcinogenic Cr6+ compounds and exhaust gases were avoided, and the water generated from vanadate precipitation may be recycled and reused in this new leaching process. The leaching residues may be easily used by a blast furnace. Moreover, (NH4)2C2O4 solution was used as a leaching medium to avoid expensive and complicated ammonium controlling operations as a result of the stability of (NH4)2C2O4 at a high temperature. The transformation mechanisms of vanadium- and chromium-bearing phases were systematically investigated by x-ray diffraction analysis and scanning electron microscopy with energy-disperse x-ray spectrometry, respectively. In addition, the effects of oxygen concentration, roasting temperature, and holding time on vanadium recovery were investigated. Finally, the effects of leaching variables on the vanadium leaching rate were also examined.

Leachability of Cr(VI) and other metals from asphalt composites with addition of filter dust.

PubMed

Vahcic, Mitja; Milacic, Radmila; Mladenovic, Ana; Murko, Simona; Zuliani, Tea; Zupancic, Marija; Scancar, Janez

2008-12-01

The potential use of filter dust in asphalt composites for road construction was investigated. Filter dust contains high concentrations of metals, of which Cr(VI) and Pb are leached with water. Compact and ground asphalt composites with addition of 2% of filter dust by mass were studied. In order to evaluate their environmental impact, leachability tests were performed using water and salt water as leaching agents. The concentrations of Cr(VI) and Pb were determined in leachates over a time period of 182 days. The results indicated that Pb was not leached with leaching agents from asphalt composites. Cr(VI) was also not leached with leaching agents from compact asphalt composites. However, in ground asphalt composites, Cr(VI) was leached with water in concentrations up to 220 microg L(-1) and in salt water up to 150 microg L(-1). From the physico-mechanical and environmental aspects, filter dust can be used as a component in asphalt mixtures.

Leaching behavior of total organic carbon, nitrogen, and phosphorus from banana peel.

PubMed

Jiang, Ruixue; Sun, Shujuan; Xu, Yan; Qiu, Xiudong; Yang, Jili; Li, Xiaochen

2015-01-01

The leaching behavior of organic carbon and nutrient compounds from banana peel (BP) was investigated in batch assays with respect to particle size, contact time, pH value, and temperature. The granularity, contact time, pH, and temperature caused no significant effects on the leaching of total phosphorus (TP) from the BP. The maximum leached total nitrogen (TN) content was found at pH 5.0 and 90 minutes, while no significant effects were caused by the granularity and temperature. The maximum leached total organic carbon (TOC) content was found by using a powder of 40 mesh, 150 minutes and at pH 6.0, while the temperature had no effect on the TOC leaching. The proportions of the TN, TP, and TOC contents leached from the dried BP ranged from 33.6% to 40.9%, 60.4% to 72.7%, and 8.2% to 9.9%, respectively, indicating that BP could be a potential pollution source for surface and ground water if discharged as domestic waste or reutilized without pretreatment.

Effect of Mechanical Activation Treatment on the Recovery of Vanadium from Converter Slag

NASA Astrophysics Data System (ADS)

Xiang, Junyi; Huang, Qingyun; Lv, Xuewei; Bai, Chenguang

2017-10-01

The high roasting temperature and low leaching efficiency of vanadium from vanadium-bearing converter slag are regarded as the main factors significantly influencing the application of calcification roasting-acid leaching processes in the cleaner production of vanadium. In this study, a mechanical activation treatment was performed to enhance the extraction of vanadium from converter slag. The enhancement effects obtained from mechanical activation were comprehensively evaluated through indices such as the roasting temperature and leaching efficiency. The effects of mechanical activation time, roasting temperature, leaching temperature, solid to liquid ratio, particle size, and acid concentration on the leaching efficiency were investigated. Microstructure morphology and elemental analyses of the raw materials and leaching residue were also investigated using scanning electron microscopy and energy-dispersive X-ray spectroscopy. The results demonstrated that the mechanical activation significantly decreased the optimum roasting temperature from 1173 K to 1073 K (900 °C to 800 °C) and increased the leaching efficiency from 86.0 to 90.9 pct.

Study on Cr(VI) Leaching from Cement and Cement Composites

PubMed Central

Palascakova, Lenka; Kanuchova, Maria

2018-01-01

This paper reports an experimental study on hexavalent chromium leaching from cement samples and cement composites containing silica fume and zeolite additions that were subjected to various leaching agents. The water-soluble Cr(VI) concentrations in cements ranged from 0.2 to 3.2 mg/kg and represented only 1.8% of the total chromium content. The presence of chromium compounds with both chromium oxidation states of III and VI was detected in the cement samples by X-ray photoelectron spectroscopy (XPS). Leaching tests were performed in a Britton-Robinson buffer to simulate natural conditions and showed increased dissolution of Cr(VI) up to 6 mg/kg. The highest amount of leached hexavalent chromium was detected after leaching in HCl. The findings revealed that the leaching of chromium from cements was higher by 55–80% than that from the cement composites. A minimum concentration was observed for all cement samples when studying the relationship between the soluble Cr(VI) and the cement storage time. PMID:29690550

Study on Cr(VI) Leaching from Cement and Cement Composites.

PubMed

Estokova, Adriana; Palascakova, Lenka; Kanuchova, Maria

2018-04-22

This paper reports an experimental study on hexavalent chromium leaching from cement samples and cement composites containing silica fume and zeolite additions that were subjected to various leaching agents. The water-soluble Cr(VI) concentrations in cements ranged from 0.2 to 3.2 mg/kg and represented only 1.8% of the total chromium content. The presence of chromium compounds with both chromium oxidation states of III and VI was detected in the cement samples by X-ray photoelectron spectroscopy (XPS). Leaching tests were performed in a Britton-Robinson buffer to simulate natural conditions and showed increased dissolution of Cr(VI) up to 6 mg/kg. The highest amount of leached hexavalent chromium was detected after leaching in HCl. The findings revealed that the leaching of chromium from cements was higher by 55⁻80% than that from the cement composites. A minimum concentration was observed for all cement samples when studying the relationship between the soluble Cr(VI) and the cement storage time.

Recovery of valuable metals from waste diamond cutters through ammonia-ammonium sulfate leaching

NASA Astrophysics Data System (ADS)

Xue, Ping; Li, Guang-qiang; Yang, Yong-xiang; Qin, Qin-wei; Wei, Ming-xing

2017-12-01

Copper and zinc were recovered from waste diamond cutters through leaching with an ammonia-ammonium sulfate system and air as an oxidant. The effects of experimental parameters on the leaching process were investigated, and the potential-pH ( E-pH) diagrams of Cu-NH3-SO4 2--H2O and Zn-NH3-SO4 2--H2O at 25°C were drawn. Results showed that the optimal parameters for the leaching reaction are as follows: reaction temperature, 45°C; leaching duration, 3 h; liquid-to-solid ratio, 50:1 (mL/g); stirring speed, 200 r/min; ammonia concentration, 4.0 mol/L; ammonium sulfate concentration, 1.0 mol/L; and air flow rate, 0.2 L/min. The results of the kinetics study indicated that the leaching is controlled by the surface chemical reaction at temperatures below 35°C, and the leaching is controlled by diffusion through the product layer at temperatures above 35°C.

The potential of oceanic transport and onshore leaching of additive-derived lead by marine macro-plastic debris.

PubMed

Nakashima, Etsuko; Isobe, Atsuhiko; Kako, Shin'ichiro; Itai, Takaaki; Takahashi, Shin; Guo, Xinyu

2016-06-15

The long-distance transport potential of toxic lead (Pb) by plastic marine debris was examined by pure water leaching experiments using plastic fishery floats containing high level of additive-Pb such as 5100±74.3mgkg(-1). The leaching of Pb ended after sequential 480-h leaching experiments, and the total leaching amount is equivalent to approximately 0.1% of total Pb in a float. But it recovered when the float was scratched using sandpaper. We propose that a "low-Pb layer," in which Pb concentration is negligibly small, be generated on the float surface by the initial leaching process. Thickness of the layer is estimated at 2.5±1.2μm, much shallower than flaws on floats scratched by sandpaper and floats littering beaches. The result suggests that the low-Pb layer is broken by physical abrasion when floats are washed ashore, and that Pb inside the floats can thereafter leach into beaches. Copyright © 2016 Elsevier Ltd. All rights reserved.

[Newly leaching method of copper from waste print circuit board using hydrochloric acid/n-butylamine/copper sulfate].

PubMed

Wang, Hong-Yan; Cui, Zhao-Jie; Yao, Ya-Wei

2010-12-01

A newly leaching method of copper from waste print circuit board was established by using hydrochloric acid-n-butylamine-copper sulfate mixed solution. The conditions of leaching were optimized by changing the hydrochloric acid, n-butylamine, copper sulfate,temperature and other conditions using copper as target mimics. The results indicated that copper could be leached completely after 8 h at 50 degrees C, hydrochloric acid concentration of 1.75 mol/L, n-butylamine concentration of 0.25 mol/L, and copper sulfate mass of 0.96 g. Under the conditions, copper leaching rates in waste print circuit board samples was up to 95.31% after 9 h. It has many advantages such as better effects, low cost, mild reaction conditions, leaching solution recycling.

Closed circuit recovery of copper, lead and iron from electronic waste with citrate solutions.

PubMed

Torres, Robinson; Lapidus, Gretchen T

2017-02-01

An integral closed circuit hydrometallurgical process is presented for base metal recovery from electronic waste. The leaching medium consists of a sodium citrate solution, from which base metals are retrieved by direct electrowinning, and the barren solution is recycled back to the leaching stage. This leaching-electrowinning cycle was repeated four times. The redox properties of the fresh citrate solution, as well as the leach liquors, were characterized by cyclic voltammetry to determine adequate conditions for metal reduction, as well as to limit citrate degradation. The leaching efficiency of electronic waste, employing the same solution after four complete cycles was 71, 83 and 94% for copper, iron and lead, respectively, compared to the original leach with fresh citrate solution. Copyright © 2016 Elsevier Ltd. All rights reserved.

Leaching of silicon from ferronickel (FeNi) smelting slag with sodium hydroxide solution at atmospheric pressure

NASA Astrophysics Data System (ADS)

Mufakhir, F. R.; Mubarok, M. Z.; Ichlas, Z. T.

2018-01-01

The present paper reports the leaching behavior of silicon from ferronickel slag under atmospheric pressure using sodium hydroxide solution. The effect of several experimental variables, namely concentration of leaching agent, operating temperature, stirring speed, and slurry density was investigated. The leaching kinetic was also investigated by using shrinking core model. It was determined that leaching of silicon from the slag was controlled by diffusion through product layer, although the activation energy was found to be 85.84 kJ/mol, which was unusually high for such a diffusion-controlled process.

Study on copper kinetics in processing sulphide ore mixed with copper and zinc with sulfuric acid leaching under pressure

NASA Astrophysics Data System (ADS)

Wen-bo, LUO; Ji-kun, WANG; Yin, GAN

2018-01-01

Sulphide ore mixed with copper and zinc is processed with pressure acid leaching. Research is conducted on the copper kinetic. The stirring rate is set at 600 rpm which could eliminate the influence of external diffusions. Research is conducted on the factors affecting the copper leaching kinetic are temperature, pressure, concentration of sulfuric acid, particle size. The result shows that the apparent activity energy is 50.7 KJ/mol. We could determine that the copper leaching process is shrinking core model of chemical reaction control and work out the leaching equation.

Project REAL (Real Educational Activities of Learning)

ERIC Educational Resources Information Center

Lindsay, Dolores

1977-01-01

Project REAL (Real Educational Activities of Learning) began as a program for 22 handicapped high school dropouts under age 21 and offered practical instruction in such areas as construction, electronic assembly, and merchandising. (JYC)

Kansas Protects and Restores Wetlands, Streams and Riparian Areas

EPA Pesticide Factsheets

Wetland Program Development Grant (WPDG) in 2007 when the Kansas State Conservation Commission began identifying team members interested in developing a framework for a comprehensive Kansas Wetland and Aquatic Resources Conservation Plan.

The Birth of the Citizenship Schools: Entwining the Struggles for Literacy and Freedom

ERIC Educational Resources Information Center

Levine, David P.

2004-01-01

This essay focuses on the formative years of the Citizenship Training Program as a Highlander project in the Charleston area. Informally known as Citizenship Schools, this adult education program began in 1958 under the sponsorship of Tennessee's Highlander Folk School, which handed over to the Southern Christian Leadership Conference (SCLC) in…

Concrete Steps for Assessing the "Soft Skills" in an MBA Program

ERIC Educational Resources Information Center

Ingols, Cynthia; Shapiro, Mary

2014-01-01

In 2006, our School of Management began the serious path of assessing both the "hard skills" (such as accounting, finance, and strategy) and the "soft skills" (such as leadership, team work, and ethics) of our MBA Program. The data generated from examining the "soft skills" that we want students to learn within our…

U.S. Foreign Assistance to the Middle East: Historical Background, Recent Trends, and the FY2011 Request

DTIC Science & Technology

2010-06-15

entrepreneurship in Jeddah, Saudi Arabia culminating in a conference in March 2010 called the U.S.-Saudi Women’s Forum on Social Entrepreneurship . The...Syria. Recent examples of MEPI-funded programs include: • Saudi Arabia—In April 2009, MEPI began funding a pilot program on women’s social

Development of a Vocabulary Building Program for Vocational Education Students.

ERIC Educational Resources Information Center

James, Bobby M.

In view of the fact that vocational education students want only the essentials of the reading curriculum, the reading center at Eastern New Mexico University (Roswell) began a program of direct vocabulary building. This method stresses application of words to be learned, making them function for the learner, as well as a high interest factor.…

Business and Industry: Partners in Education of Gifted and Talented.

ERIC Educational Resources Information Center

Treloar, Donald N.

In 1969 the Newark, New Jersey, Board of Education began the School Within A School Program for gifted and talented inner-city high school students. The program, offering an eleven-month school year plus five major subjects, uses the resources of business and industry to prepare students for a college education. An advisory board consisting of…

Culture and Career: Community for Education.

ERIC Educational Resources Information Center

Bovee, Charles C.; Binau, David K.

During the past 8 to 10 years education at Sheldon Jackson College (SJC) has shifted to a theme of culture and careers. This paper describes current SJC programs, as well as some that are being considered. The Culture and Native Study Programs, funded in 1968, began with the teaching of the Tlingit Language. As a result, the First Tlingit Language…

RESEARCH MEMORANDUM, EVALUATION OF AN INSERVICE TELEVISION TRAINING PROGRAM IN MATHEMATICS FOR ELEMENTARY TEACHERS.

ERIC Educational Resources Information Center

KOPSTEIN, FELIX F.; MILLS, DONALD F.

AN EVALUATION WAS CONDUCTED TO ANSWER THREE QUESTIONS--(1) HOW MUCH DID ELEMENTATY SCHOOL TEACHERS WHO VIEWED INSTRUCTIONAL TELECASTS ON MODERN MATHEMATICS KNOW ABOUT THE NEWER MATHEMATICAL CONCEPTS BEFORE THE SERIES OF PROGRAMS BEGAN, AND WHAT WERE THEIR ATTITUDES, (2) HOW MUCH DID THE TEACHERS KNOW, AND HOW MUCH WERE THEIR ATTITUDES CHANGED…

Programs That Work, from the Promising Practices Network on Children, Families and Communities. RAND Tool

ERIC Educational Resources Information Center

Kilburn, M. Rebecca, Ed.

2014-01-01

The Promising Practices Network (PPN) on Children, Families and Communities (www.promisingpractices.net) began as a partnership between four state-level organizations that help public and private organizations improve the well-being of children and families. The PPN website, archived in June 2014, featured summaries of programs and practices that…

Engaging the Disengaged: How Is It Different When Using Distance Education?

ERIC Educational Resources Information Center

Gross, Peggy

In response to large numbers of returning adult students, Wisconsin's technical college system has placed an increased emphasis on school-to-work transition and innovative forms of distance education (DE). DE began in Europe at least 150 years ago through correspondence programs, expanded to include radio programs in the 1920s and 1930s, and moved…

Youth Chance. A Program of the San Francisco Mayor's Office of Employment and Training.

ERIC Educational Resources Information Center

Lesser & Ogden Associates, San Francisco, CA.

The San Francisco-based YMCA Youth Chance began in 1978 as a Youth Community Conservation and Improvement "sweat program"--a means of providing unemployed high school dropouts with CETA (Comprehensive Employment and Training Act)-funded jobs. Youth Chance continues to train males and females, 16-19 years of age, who meet CETA…

The Missouri Southern Story: From the Provincial to the International

ERIC Educational Resources Information Center

Mills, Kay

2007-01-01

This article describes the international program at Missouri Southern, which began 10 years ago and has expanded in both the number of students and faculty participating, and in the places to go for foreign study. The program affects students two ways, according to university president Julio Leon. While some students do foreign study as part of…

Progress and challenges of protecting North American ash trees from the emerald ash borer using biological control

Treesearch

Jian Duan; Leah Bauer; Roy van Driesche; Juli Gould

2018-01-01

After emerald ash borer (EAB), Agrilus planipennis Fairmaire, was discovered in the United States, a classical biological control program was initiated against this destructive pest of ash trees (Fraxinus spp.). This biocontrol program began in 2007 after federal regulatory agencies and the state of Michigan approved release of...

Reverse Transfer: Experiences of International Chinese Students in Intensive English Programs

ERIC Educational Resources Information Center

Zhang, Yi

2015-01-01

An increasing number of international Chinese undergraduate students enrolled in United States.colleges and universities in the past few years. Many began their journey in an intensive English program of a four-year university due to lack of English proficiency. Instead of continuing their study at the same institution, a considerable number of…

Language Camps: Thirteen Years of Minor Miracles.

ERIC Educational Resources Information Center

Peterson, Jean

A language camp program that began with a small group of 10- to 12-year-olds whose faculty parents wanted them to retain the German learned on sabbaticals abroad has developed into a program of annual week-long day and resident camps for 150 children, aged 9 to 14 years, learning German, French, Spanish, and Norwegian. The camp was originally…

The Impact of Internet Subsidies in Public Schools. NBER Working Paper Series.

ERIC Educational Resources Information Center

Goolsbee, Austan; Guryan, Jonathan

As part of the Telecommunications Act of 1996, the U.S. government began subsidizing Internet and telecommunications access in classrooms and libraries through a tax on long-distance services (the E-Rate Program). This paper analyzes the impact of this program on public schools' technology adoption during 1996-2000, examining data on technology…

An Evaluation of the Chicago Teacher Advancement Program (Chicago TAP) after Four Years. Final Report

ERIC Educational Resources Information Center

Glazerman, Steven; Seifullah, Allison

2012-01-01

In 2007, using funds from the federal Teacher Incentive Fund (TIF) and private foundations, the Chicago Public Schools (CPS) began piloting its version of a schoolwide reform model called the Teacher Advancement Program (TAP). Under the TAP model, teachers can earn extra pay and take on increased responsibilities through promotion (to mentor…

An Evaluation of the Teacher Advancement Program (TAP) in Chicago: Year Two Impact Report

ERIC Educational Resources Information Center

Glazerman, Steven; Seifullah, Allison

2010-01-01

In 2007, the Chicago Public Schools (CPS) began implementing a schoolwide reform called the Teacher Advancement Program (TAP) using funds from the federal Teacher Incentive Fund (TIF) and private foundations. Under the TAP model, teachers can earn extra pay and responsibilities through promotion to mentor or master teacher as well as annual…

The Exploratorium's XTech Program: Engaging STEM Experiences for Middle-School Youth. Summative Evaluation Report

ERIC Educational Resources Information Center

Carroll, Becky; Smith, Anita; Castori, Pam

2009-01-01

The Exploratorium is home to XTech, a science education program which began in 2006 and was primarily funded by a three-year National Science Foundation grant (Award # 05-25217) through its ITEST (Innovative Technology Experiences for Students and Teachers) initiative. XTech provided project-based afterschool activities in science, engineering,…

A History of Early Childhood Education in Canada, Australia, and New Zealand

ERIC Educational Resources Information Center

Prochner, Larry

2009-01-01

In the early nineteenth century, governments began to develop specialized educational programs--kindergartens and infant or nursery schools--to give children a head start in life. These programs hinged on new visions of childhood that originated in England and Europe, but what happened when they were transported to the colonies? This book unwinds…

The Social Battleground of School Improvement: When a Troubled School Is Impacted by an Intensive Renewal Program.

ERIC Educational Resources Information Center

Sudderth, Charlotte R.

Long considered by its community and the Richmond County Schools' district administration "the worst middle school in the distict," the school (unnamed in the study) began a process of change in spring 1987. The instructional staff embraced a schoolwide staff development program designed to help both student achievement and school…

American Indian Studies as an Academic Discipline

ERIC Educational Resources Information Center

Kidwell, Clara Sue

2011-01-01

When American Indian/Native American studies (AI/NAS) programs began to emerge in the halls of academia during the late 1960s and early 1970s, some who served as faculty and staff questioned whether they would be one-generation phenomena. Would the programs survive, would they continue to draw students, and could they make an impact on…

Addressing the Employment Situation in the Aftermath of the Great Recession

ERIC Educational Resources Information Center

Neumark, David; Troske, Kenneth

2012-01-01

Since U.S. economic growth began to slow in 2006, both the Bush and Obama Administrations have enacted a number of fairly costly programs designed to stimulate the economy and employment growth. Because many of these programs are fairly new, there has been little comprehensive examination of their impacts, but initial analysis suggests that these…

Middle School Mathematics: A Study of Three Programs in South Texas

ERIC Educational Resources Information Center

Ellis, Joanetta Dowell

2011-01-01

In 2010, the Texas Assessment of Knowledge and Skills (TAKS) began its seventh year of testing (Texas Education Agency, 2009a). High stakes testing is a reality. This study considered the impact on mathematics achievement based on the mathematics program students were receiving during their middle school years. The purpose of this study was to…

Rural Teacher Education for the 21st Century: A Minnesota Outreach Model.

ERIC Educational Resources Information Center

Halcrow, John H.

In 1986 Bemidji State University (BSU), located in rural northern Minnesota, began an outreach distance learning program for the preservice education of elementary teachers. This college program delivers junior and senior year education courses to students 100 miles plus from the main campus. Junior and senior year requirements are completed in a…

Does State Aid Stimulate Public Library Expenditures? Evidence from Pennsylvania's Enhancement Aid Program

ERIC Educational Resources Information Center

Stine, William F.

2006-01-01

Pennsylvania public libraries began receiving increased allotments of state aid in 2000. In the first two years of enhancement aid, total state aid received by Pennsylvania libraries more than doubled. This reversed the trend of little growth in the years preceding 2000. The enhancement aid program also redesigned certain categories of state aid…

Case Studies of 19 School Resource Officer (SRO) Programs. Document Number 209271

ERIC Educational Resources Information Center

Finn, Peter; McDevitt, Jack; Lassiter, William; Shively, Michael; Rich, Tom

2005-01-01

There has been a growing interest in placing sworn law enforcement officers in schools as School Resource Officers (SROs) as a means of improving school safety and improving relations between police officers and youth. However, when this project began in May 2000, relatively little was known about SRO programs. The purpose of the National…

Evolution of collaboration within the US long term ecological research network

Treesearch

Jeffrey C. Johnson; Robert R. Christian; James W. Brunt; Caleb R. Hickman; Robert B. Waide

2010-01-01

The US Long Term Ecological Research (LTER) program began in 1980 with the mission of addressing long-term ecological phenomena through research at individual sites, as well as comparative and synthetic activities among sites. We applied network science measures to assess how the LTER program has achieved its mission using intersite publications as the measure of...

Program Cost Accounting Manual. Form J-380/Form J-580, 1989-90.

ERIC Educational Resources Information Center

California State Dept. of Education, Sacramento. Office of Financial Management Practices and Standards.

In response to criticism by legislators, the business community, and other publics for an apparent lack of sound financial management, the California State Department of Education, together with representatives from the field and from state control agencies, began to develop a new program cost accounting system in 1984. After pilot testing, the…

Establishing a Research Agenda for American Indian and Alaska Native Head Start Programs

ERIC Educational Resources Information Center

Marks, Ellen L.; Graham, Elliott T.

2004-01-01

Since it began in 1965, Head Start has been the cornerstone of the nation's services for low-income children and their families. A substantial research base has been attached to Head Start, providing information about the program's overall accomplishments and directions about ways to improve services for young children. American Indian and Alaska…

A Five-Year Follow-Up of Students Enrolled in Post-Secondary Vocational-Technical-Transfer Programs.

ERIC Educational Resources Information Center

Noeth, Richard J.; Hanson, Gary R.

The nationwide study examines career behavior patterns and work orientations of students five years after they began vocational-technical transfer programs at community colleges, technical schools, and similar kinds of institutions in the fall of 1970. The study sample consisted of 4,350 individuals selected from the national norm group who…

4-H Healthy Living Programs with Impact: A National Environmental Scan

ERIC Educational Resources Information Center

Downey, Laura H.; Peterson, Donna J.; LeMenestrel, Suzanne; Leatherman, JoAnne; Lang, James

2014-01-01

The 4-H youth development program of the nation's 109 land-grant universities and the Cooperative Extension System is one of the largest youth development organization in the United States serving approximately six million youth. The 4-H Healthy Living initiative began in 2008 to promote achievement of optimal physical, social, and emotional…

Valuing Brazilian Youth: IDRA's Coca Cola Valued Youth Program in Latin America

ERIC Educational Resources Information Center

Montecel, Maria Robledo

2008-01-01

Intercultural Development Research Association (IDRA) is an independent, non-profit organization with a vision for schools that work for all children. It partnered with Coca-Cola in 1984 and began a dropout prevention program just as it was conducting the first comprehensive study of school dropouts in Texas. Its annual studies since then have…

The Fiscal Impact of the D.C. Voucher Program

ERIC Educational Resources Information Center

Aud, Susan L.; Michos, Leon

2006-01-01

In August 2004 the first ever federally funded school voucher program began in Washington, D.C. Eligible students could attend a private school of their choice in the District of Columbia. Each participant received up to $7,500 for school tuition, fees, and transportation. In addition, the D.C. Public School System (DCPS) and D.C. charter school…

Weatherability and leach resistance of wood impregnated with nano-zinc oxide

Treesearch

Carol A. Clausen; Frederick Green; S. Nami Kartal

2010-01-01

Southern pine specimens vacuum-treated with nano-zinc oxide (nano-ZnO) dispersions were evaluated for leach resistance and UV protection. Virtually, no leaching occurred in any of the nano-ZnO–treated specimens in a laboratory leach test, even at the highest retention of 13 kg/m3. However, specimens treated with high concentrations of nano-ZnO...

Rare-earth leaching from Florida phosphate rock in wet-process phosphoric acid production

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liang, Haijun; Zhang, Patrick; Jin, Zhen

Phosphorite, or phosphate rock, is the most significant secondary rare-earth resource. It contains high amounts of phosphate-bearing minerals along with low contents of rare earth elements (REEs). In Florida, about 19 Mt of phosphate rock are mined annually and most are used to manufacture fertilizers using a wet process, in which sulfuric acid reacts with phosphates to produce phosphoric acid and phosphogypsum. In the wet process, REEs are also leached out into solution and eventually get lost in the leaching residue and phosphate fertilizer. Recovering REEs from Florida phosphate rock in the wet process will be beneficial to broadening rare-earthmore » availability, improving the quality of phosphoric acid product and protecting the environment. Here, this study focuses on the influences of wet-process operating conditions on REE leaching efficiency. The results indicate that REE leaching efficiency increases with phosphoric acid addition in the initial pulp. At a temperature of 75 °C, a stoichiometric ratio of sulfuric acid (H2 SO4 ) to calcium oxide (CaO) of 1.05 and a weight ratio of liquid to solid of 3.5, REE leaching efficiency reached a relatively high value of 52.82 percent. The trends of REE leaching efficiency were similar to those for phosphoric acid (P2O5 ). Extensive tests on the leaching residue showed that during leaching, about 90 percent of the REEs were released from the phosphate rock but only 52.82 percent ended up in the leaching solution. This phenomenon can be attributed to two factors: (1) the effect of phosphate ions (PO43-) in the solution, which caused REE ions to form REE phosphates and be precipitated into the leaching residue, and (2) the influence of large amounts of anions such as sulfate (SO42-), dihydrogen phosphate (H2 PO4-) and hydrogen phosphate (HPO42-) anions as well as the polar molecule H3 PO4 , which surrounded the REE cations and formed an ion atmosphere that prevented the PO43- from contacting and combining with REE cations. Finally, interaction of these two opposite effects determined the REE distribution between leaching solution and residue.« less

Rare-earth leaching from Florida phosphate rock in wet-process phosphoric acid production

DOE PAGES

Liang, Haijun; Zhang, Patrick; Jin, Zhen; ...

2017-08-01

Phosphorite, or phosphate rock, is the most significant secondary rare-earth resource. It contains high amounts of phosphate-bearing minerals along with low contents of rare earth elements (REEs). In Florida, about 19 Mt of phosphate rock are mined annually and most are used to manufacture fertilizers using a wet process, in which sulfuric acid reacts with phosphates to produce phosphoric acid and phosphogypsum. In the wet process, REEs are also leached out into solution and eventually get lost in the leaching residue and phosphate fertilizer. Recovering REEs from Florida phosphate rock in the wet process will be beneficial to broadening rare-earthmore » availability, improving the quality of phosphoric acid product and protecting the environment. Here, this study focuses on the influences of wet-process operating conditions on REE leaching efficiency. The results indicate that REE leaching efficiency increases with phosphoric acid addition in the initial pulp. At a temperature of 75 °C, a stoichiometric ratio of sulfuric acid (H2 SO4 ) to calcium oxide (CaO) of 1.05 and a weight ratio of liquid to solid of 3.5, REE leaching efficiency reached a relatively high value of 52.82 percent. The trends of REE leaching efficiency were similar to those for phosphoric acid (P2O5 ). Extensive tests on the leaching residue showed that during leaching, about 90 percent of the REEs were released from the phosphate rock but only 52.82 percent ended up in the leaching solution. This phenomenon can be attributed to two factors: (1) the effect of phosphate ions (PO43-) in the solution, which caused REE ions to form REE phosphates and be precipitated into the leaching residue, and (2) the influence of large amounts of anions such as sulfate (SO42-), dihydrogen phosphate (H2 PO4-) and hydrogen phosphate (HPO42-) anions as well as the polar molecule H3 PO4 , which surrounded the REE cations and formed an ion atmosphere that prevented the PO43- from contacting and combining with REE cations. Finally, interaction of these two opposite effects determined the REE distribution between leaching solution and residue.« less

The pH-dependent contaminant leaching from the copper smelter fly ash and slag

NASA Astrophysics Data System (ADS)

Jarosikova, Alice; Ettler, Vojtech; Mihaljevic, Martin; Penizek, Vit

2014-05-01

Metallurgical wastes produced during smelting processes represent a potential risk of environmental contamination, depending particularly on the content and mobility of the elements contained. Due to leaching, serious environmental impact especially in contaminated soil systems in the vicinity of the smelting plants may occur. In this respect two potentially hazardous metallurgical wastes from the copper smelter Tsumeb (Namibia, Africa) were investigated by laboratory leaching experiments. The leaching behaviours of (i) Ausmelt slag from Cu smelting (9500 ppm As, 24000 ppm Cu, 10200 ppm Pb, 24500 ppm Zn; mineralogy: glass, fayalite, spinel, metallic/sulphide droplets) and (ii) fly ash from Cu smelter bag house filters (43.7 wt% As, 13000 ppm Cu, 39700 ppm Pb, 20000 ppm Zn; mineralogy: arsenolite, galena, gypsum, litharge, anglesite) were studied using a 48-h pH-static leaching test (CEN/TS 14997). The release of metals/metalloids at a range of pH 3-12, investigation of changes in mineralogical composition and PHREEQC speciation-solubility modelling were used to understand processes governing the contaminant leaching from these waste materials. It was observed that the contaminant leaching was highly pH-dependent. The release of metals from slag corresponded to "L-type" leaching curve with Cu being the key contaminant leached (up to 1780 mg/kg). In contrast, As was highly leached also in alkaline conditions (31-173 mg/kg) and significantly exceeded the limit value for hazardous waste materials in all cases (25 mg/kg). Fly ash was found to be extremely reactive in terms of the As release with a "J-type" leaching curve indicating the highest leaching at pH of 11 and 12 (up to 314 g/kg). Arsenic was considered to be the most important contaminant for both waste materials and its release can represent a risk for the environment, especially in case, where the fly ash- or slag-derived particulates are deposited into the soil systems. This study was supported by the Czech Science Foundation (projects no. 13-17501S and P210/12/1413) and IGCP project no. 594.

Simultaneous recovery of Ni and Cu from computer-printed circuit boards using bioleaching: statistical evaluation and optimization.

PubMed

Arshadi, M; Mousavi, S M

2014-12-01

Computer printed circuit boards (CPCBs) have a rich metal content and are produced in high volume, making them an important component of electronic waste. The present study used a pure culture of Acidithiobacillus ferrooxidans to leach Cu and Ni from CPCBs waste. The adaptation phase began at 1g/l CPCBs powder with 10% inoculation and final pulp density was reached at 20g/l after about 80d. Four effective factors including initial pH, particle size, pulp density, and initial Fe(3+) concentration were optimized to achieve maximum simultaneous recovery of Cu and Ni. Their interactions were also identified using central composite design in response surface methodology. The suggested optimal conditions were initial pH 3, initial Fe(3+) 8.4g/l, pulp density 20g/l and particle size 95μm. Nearly 100% of Cu and Ni were simultaneously recovered under optimum conditions. Finally, bacterial growth characteristics versus time at optimum conditions were plotted. Copyright © 2014 Elsevier Ltd. All rights reserved.

Physical and chemical mechanism underlying ultrasonically enhanced hydrochloric acid leaching of non-oxidative roasting of bastnaesite.

PubMed

Zhang, Dongliang; Li, Mei; Gao, Kai; Li, Jianfei; Yan, Yujun; Liu, Xingyu

2017-11-01

In this study, we investigated an alternative to the conventional hydrochloric acid leaching of roasted bastnaesite. The studies suggested that the rare earth oxyfluorides in non-oxidatively roasted bastnaesite can be selectively leached only at elevated temperatures Further, the Ce(IV) in oxidatively roasted bastnaesite does not leach readily at low temperatures, and it is difficult to induce it to form a complex with F - ions in order to increase the leaching efficiency. Moreover, it is inevitably reduced to Ce(III) at elevated temperatures. Thus, the ultrasonically-assisted hydrochloric acid leaching of non-oxidatively roasted bastnaesite was studied in detail, including, the effects of several process factors and the, physical and chemical mechanisms underlying the leaching process. The results show that the leaching rate for the ultrasonically assisted process at 55°C (65% rare earth oxides) is almost the same as that for the conventional leaching process at 85°C. Based on the obtained results, it is concluded that ultrasonic cavitation plays a key role in the proposed process, resulting not only in a high shear stress, which damages the solid surface, but also in the formation of hydroxyl radicals (OH) and hydrogen peroxide (H 2 O 2 ). Standard electrode potential analysis and experimental results indicate that Ce(III) isoxidized by the hydroxyl radicals to Ce(IV), which can be leached with F - ions in the form of a complex, and that the Ce(IV) can subsequently be reduced to Ce(III) by the H 2 O 2. This prevents the Cl - ions in the solution from being oxidized to form chlorine. These results imply that the ultrasonically-assisted process can be used for the leaching of non-oxidatively roasted bastnaesite at low temperatures in the absence of a reductant. Copyright © 2017 Elsevier B.V. All rights reserved.

Life cycle assessment and residue leaching: The importance of parameter, scenario and leaching data selection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Allegrini, E., E-mail: elia@env.dtu.dk; Butera, S.; Kosson, D.S.

Highlights: • Relevance of metal leaching in waste management system LCAs was assessed. • Toxic impacts from leaching could not be disregarded. • Uncertainty of toxicity, due to background activities, determines LCA outcomes. • Parameters such as pH and L/S affect LCA results. • Data modelling consistency and coverage within an LCA are crucial. - Abstract: Residues from industrial processes and waste management systems (WMSs) have been increasingly reutilised, leading to landfilling rate reductions and the optimisation of mineral resource utilisation in society. Life cycle assessment (LCA) is a holistic methodology allowing for the analysis of systems and products andmore » can be applied to waste management systems to identify environmental benefits and critical aspects thereof. From an LCA perspective, residue utilisation provides benefits such as avoiding the production and depletion of primary materials, but it can lead to environmental burdens, due to the potential leaching of toxic substances. In waste LCA studies where residue utilisation is included, leaching has generally been neglected. In this study, municipal solid waste incineration bottom ash (MSWI BA) was used as a case study into three LCA scenarios having different system boundaries. The importance of data quality and parameter selection in the overall LCA results was evaluated, and an innovative method to assess metal transport into the environment was applied, in order to determine emissions to the soil and water compartments for use in an LCA. It was found that toxic impacts as a result of leaching were dominant in systems including only MSWI BA utilisation, while leaching appeared negligible in larger scenarios including the entire waste system. However, leaching could not be disregarded a priori, due to large uncertainties characterising other activities in the scenario (e.g. electricity production). Based on the analysis of relevant parameters relative to leaching, and on general results of the study, recommendations are provided regarding the use of leaching data in LCA studies.« less

Valorization of GaN based metal-organic chemical vapor deposition dust a semiconductor power device industry waste through mechanochemical oxidation and leaching: A sustainable green process

DOE Office of Scientific and Technical Information (OSTI.GOV)

Swain, Basudev, E-mail: Swain@iae.re.kr; Mishra, Chinmayee; Lee, Chan Gi

2015-07-15

Dust generated during metal organic vapor deposition (MOCVD) process of GaN based semiconductor power device industry contains significant amounts of gallium and indium. These semiconductor power device industry wastes contain gallium as GaN and Ga{sub 0.97}N{sub 0.9}O{sub 0.09} is a concern for the environment which can add value through recycling. In the present study, this waste is recycled through mechanochemical oxidation and leaching. For quantitative recovery of gallium, two different mechanochemical oxidation leaching process flow sheets are proposed. In one process, first the Ga{sub 0.97}N{sub 0.9}O{sub 0.09} of the MOCVD dust is leached at the optimum condition. Subsequently, the leachmore » residue is mechanochemically treated, followed by oxidative annealing and finally re-leached. In the second process, the MOCVD waste dust is mechanochemically treated, followed by oxidative annealing and finally leached. Both of these treatment processes are competitive with each other, appropriate for gallium leaching and treatment of the waste MOCVD dust. Without mechanochemical oxidation, 40.11 and 1.86 w/w% of gallium and Indium are leached using 4 M HCl, 100 °C and pulp density of 100 kg/m{sup 3,} respectively. After mechanochemical oxidation, both these processes achieved 90 w/w% of gallium and 1.86 w/w% of indium leaching at their optimum condition. - Highlights: • Waste MOCVD dust is treated through mechanochemical leaching. • GaN is hardly leached, and converted to NaGaO{sub 2} through ball milling and annealing. • Process for gallium recovery from waste MOCVD dust has been developed. • Thermal analysis and phase properties of GaN to Ga{sub 2}O{sub 3} and GaN to NaGaO{sub 2} is revealed. • Solid-state chemistry involved in this process is reported.« less

Evaluation of heavy metal leaching from coal ash-versus conventional concrete monoliths and debris.

PubMed

Gwenzi, Willis; Mupatsi, Nyarai M

2016-03-01

Application of coal ash in construction materials is constrained by the potential risk of heavy metal leaching. Limited information is available on the comparative heavy metal leaching from coal ash-versus conventional concrete. The current study compared total and leached heavy metal concentrations in unbound coal ash, cement and sand; and investigated the effect of initial leachant pH on heavy metal leaching from coal-ash versus conventional concrete monoliths and their debris. Total Pb, Mn and Zn in coal ash were lower than or similar to that of other materials, while Cu and Fe showed the opposite trend. Leached concentrations of Zn, Pb, Mn, Cu and Fe in unbound coal ash, its concrete and debris were comparable and in some cases even lower than that for conventional concrete. In all cases, leached concentrations accounted for just <1% of the total concentrations. Log-log plots of concentration and cumulative release of Fe versus time based on tank leaching data showed that leaching was dominated by diffusion. Overall, the risk of Zn, Pb, Mn, Cu and Fe leaching from coal ash and its concrete was minimal and comparable to that of conventional concrete, a finding in contrast to widely held public perceptions and earlier results reported in other regions such as India. In the current study the coal ash, and its concrete and debris had highly alkaline pH indicative of high acid neutralizing and pH buffering capacity, which account for the stabilization of Zn, Pb, Mn, Cu and Fe. Based on the low risk of Zn, Pb, Mn, Cu and Fe leaching from the coal ash imply that such coal ash can be incorporated in construction materials such as concrete without adverse impacts on public and environmental health from these constituents. Copyright © 2015 Elsevier Ltd. All rights reserved.

Nitrate Leaching from Winter Cereal Cover Crops Using Undisturbed Soil-Column Lysimeters.

PubMed

Meisinger, John J; Ricigliano, Kristin A

2017-05-01

Cover crops are important management practices for reducing nitrogen (N) leaching, especially in the Chesapeake Bay watershed, which is under total maximum daily load (TMDL) restraints. Winter cereals are common cool-season crops in the Bay watershed, but studies have not directly compared nitrate-N (NO-N) leaching losses from these species. A 3-yr cover crop lysimeter study was conducted in Beltsville, MD, to directly compare NO-N leaching from a commonly grown cultivar of barley ( L.), rye ( L.), and wheat ( L.), along with a no-cover control, using eight tension-drained undisturbed soil column lysimeters in a completely randomized design with two replicates. The lysimeters were configured to exclude runoff and to estimate NO-N leaching and flow-weighted NO-N concentration (FWNC). The temporal pattern of NO-N leaching showed a consistent highly significant ( < 0.001) effect of lower NO-N leaching with cover crops compared with no cover but showed only small and periodically significant ( < 0.05) effects among the cultivars of barley, rye, and wheat covers. Nitrate-N leaching was more affected by the quantity of establishment-season (mid-October to mid-December) precipitation than by cover crop species. For example, compared with no cover, winter cereal covers reduced NO-N leaching 95% in a dry year and 50% in wet years, with corresponding reductions in FWNC of 92 and 43%, respectively. These results are important for scientists, nutrient managers, and policymakers because they directly compare NO-N leaching from winter cereal covers and expand knowledge for developing management practices for winter cereals that can improve water quality and increase N efficiency in cropping systems. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Different low-molecular-mass organic acids specifically control leaching of arsenic and lead from contaminated soil.

PubMed

Ash, Christopher; Tejnecký, Václav; Borůvka, Luboš; Drábek, Ondřej

2016-04-01

Low-molecular-mass organic acids (LMMOA) are of key importance for mobilisation and fate of metals in soil, by functioning as ligands that increase the amount of dissolved metal in solution or by dissociation of metal binding minerals. Column leaching experiments were performed on soil polluted with As and Pb, in order to determine the specificity of LMMOA related release for individual elements, at varying organic acid concentrations. Acetic, citric and oxalic acids were applied in 12h leaching experiments over a concentration range (0.5-25 mM) to soil samples that represent organic and mineral horizons. The leaching of As followed the order: oxalic>citric>acetic acid in both soils. Arsenic leaching was attributed primarily to ligand-enhanced dissolution of mineral oxides followed by As released into solution, as shown by significant correlation between oxalic and citric acids and content of Al and Fe in leaching solutions. Results suggest that subsurface mineral soil layers are more vulnerable to As toxicity. Leaching of Pb from both soils followed the order: citric>oxalic>acetic acid. Mineral soil samples were shown to be more susceptible to leaching of Pb than samples characterised by a high content of organic matter. The leaching efficiency of citric acid was attributed to formation of stable complexes with Pb ions, which other acids are not capable of. Results obtained in the study are evidence that the extent of As and Pb leaching in contaminated surface and subsurface soil depends significantly on the types of carboxylic acid involved. The implications of the type of acid and the specific element that can be mobilised become increasingly significant where LMMOA concentrations are highest, such as in rhizosphere soil. Copyright © 2016 Elsevier B.V. All rights reserved.

Hazardous properties of paint residues from the furniture industry.

PubMed

Vaajasaari, Kati; Kulovaara, Maaret; Joutti, Anneli; Schultz, Eija; Soljamo, Kari

2004-01-30

The objective of this study was to screen nine excess paint residues for environmental hazard and to evaluate their disposability in a non-hazardous or hazardous-waste landfill. These residues were produced in the process of spray-painting furniture. Residues were classified according to their leaching and ecotoxicological properties. Leaching properties were determined with the European standard SFS-EN 12457-2 leaching-test. The toxicity of the leaching-test eluates was measured with plant-, bacteria- and enzyme-inhibition bioassays. Total organic carbon, formaldehyde and solvent concentrations in the solid wastes and in the leaching-test eluates were analysed. It seemed likely that leached formaldehyde caused very high acute toxicity in leaching-test eluates of the dry-booth residues. This hypothesis was based on the fact that the formaldehyde concentrations in the leaching-test eluates of the dry-booth residues were 62-75 times higher than the EC50 value reported in the literature for formaldehyde. The results of the water-curtain booth residues showed that the samples with the highest TOC and aromatic solvent concentrations were also the most toxic. The studied excess paint residues were complex organic mixtures and contained large amounts of compounds not identifiable from chemical data. Therefore, the evaluation of the hazard based solely on available chemical data is unlikely to be sufficient, as evidenced by our study. Our results show that harmful compounds remain in the solid waste and the toxicity results of their leaching-test eluates show that toxicity may leach from residues in contact with water at landfill sites. They also confirm the benefit of combining chemical and ecotoxicological assays in assessing the potential environmental hazard of complex organic mixtures found in wastes. Copyright 2003 Elsevier B.V.

Coal fly ash interaction with environmental fluids: Geochemical and strontium isotope results from combined column and batch leaching experiments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brubaker, Tonya M; Stewart, Brian W; Capo, Rosemary C

2013-05-01

The major element and Sr isotope systematics and geochemistry of coal fly ash and its interactions with environmental waters were investigated using laboratory flow-through column leaching experiments (sodium carbonate, acetic acid, nitric acid) and sequential batch leaching experiments (water, acetic acid, hydrochloric acid). Column leaching of Class F fly ash samples shows rapid release of most major elements early in the leaching procedure, suggesting an association of these elements with soluble and surface bound phases. Delayed release of certain elements (e.g., Al, Fe, Si) signals gradual dissolution of more resistant silicate or glass phases as leaching continues. Strontium isotope resultsmore » from both column and batch leaching experiments show a marked increase in {sup 87}Sr/{sup 86}Sr ratio with continued leaching, yielding a total range of values from 0.7107 to 0.7138. For comparison, the isotopic composition of fluid output from a fly ash impoundment in West Virginia falls in a narrow range around 0.7124. The experimental data suggest the presence of a more resistant, highly radiogenic silicate phase that survives the combustion process and is leached after the more soluble minerals are removed. Strontium isotopic homogenization of minerals in coal does not always occur during the combustion process, despite the high temperatures encountered in the boiler. Early-released Sr tends to be isotopically uniform; thus the Sr isotopic composition of fly ash could be distinguishable from other sources and is a useful tool for quantifying the possible contribution of fly ash leaching to the total dissolved load in natural surface and ground waters.« less

Leaching of CCA-treated wood: implications for waste disposal.

PubMed

Townsend, Timothy; Tolaymat, Thabet; Solo-Gabriele, Helena; Dubey, Brajesh; Stook, Kristin; Wadanambi, Lakmini

2004-10-18

Leaching of arsenic, chromium, and copper from chromated copper arsenate (CCA)-treated wood poses possible environmental risk when disposed. Samples of un-weathered CCA-treated wood were tested using a variety of the US regulatory leaching procedures, including the toxicity characteristic leaching procedure (TCLP), synthetic precipitation leaching procedure (SPLP), extraction procedure toxicity method (EPTOX), waste extraction test (WET), multiple extraction procedure (MEP), and modifications of these procedures which utilized actual MSW landfill leachates, a construction and demolition (C and D) debris leachate, and a concrete enhanced leachate. Additional experiments were conducted to assess factors affecting leaching, such as particle size, pH, and leaching contact time. Results from the regulatory leaching tests provided similar results with the exception of the WET, which extracted greater quantities of metals. Experiments conducted using actual MSW leachate, C and D debris leachate, and concrete enhanced leachate provided results that were within the same order of magnitude as results obtained from TCLP, SPLP, and EPTOX. Eleven of 13 samples of CCA-treated dimensional lumber exceeded the US EPA's toxicity characteristic (TC) threshold for arsenic (5 mg/L). If un-weathered arsenic-treated wood were not otherwise excluded from the definition of hazardous waste, it frequently would require management as such. When extracted with simulated rainwater (SPLP), 9 of the 13 samples leached arsenic at concentrations above 5 mg/L. Metal leachability tended to increase with decreasing particle size and at pH extremes. All three metals leached above the drinking water standards thus possibly posing a potential risk to groundwater. Arsenic is a major concern from a disposal point of view with respect to ground water quality.

Leaching of glyphosate and amino-methylphosphonic acid from Danish agricultural field sites.

PubMed

Kjaer, Jeanne; Olsen, Preben; Ullum, Marlene; Grant, Ruth

2005-01-01

Pesticide leaching is an important process with respect to contamination risk to the aquatic environment. The risk of leaching was thus evaluated for glyphosate (N-phosphonomethyl-glycine) and its degradation product AMPA (amino-methylphosphonic acid) under field conditions at one sandy and two loamy sites. Over a 2-yr period, tile-drainage water, ground water, and soil water were sampled and analyzed for pesticides. At a sandy site, the strong soil sorption capacity and lack of macropores seemed to prevent leaching of both glyphosate and AMPA. At one loamy site, which received low precipitation with little intensity, the residence time within the root zone seemed sufficient to prevent leaching of glyphosate, probably due to degradation and sorption. Minor leaching of AMPA was observed at this site, although the concentration was generally low, being on the order of 0.05 microg L(-1) or less. At another loamy site, however, glyphosate and AMPA leached from the root zone into the tile drains (1 m below ground surface [BGS]) in average concentrations exceeding 0.1 microg L(-1), which is the EU threshold value for drinking water. The leaching of glyphosate was mainly governed by pronounced macropore flow occurring within the first months after application. AMPA was frequently detected more than 1.5 yr after application, thus indicating a minor release and limited degradation capacity within the soil. Leaching has so far been confined to the depth of the tile drains, and the pesticides have rarely been detected in monitoring screens located at lower depths. This study suggests that as both glyphosate and AMPA can leach through structured soils, they thereby pose a potential risk to the aquatic environment.

Chemical associations and mobilization of heavy metals in fly ash from municipal solid waste incineration.

PubMed

Weibel, Gisela; Eggenberger, Urs; Schlumberger, Stefan; Mäder, Urs K

2017-04-01

This study focusses on chemical and mineralogical characterization of fly ash and leached filter cake and on the determination of parameters influencing metal mobilization by leaching. Three different leaching processes of fly ash from municipal solid waste incineration (MSWI) plants in Switzerland comprise neutral, acidic and optimized acidic (+ oxidizing agent) fly ash leaching have been investigated. Fly ash is characterized by refractory particles (Al-foil, unburnt carbon, quartz, feldspar) and newly formed high-temperature phases (glass, gehlenite, wollastonite) surrounded by characteristic dust rims. Metals are carried along with the flue gas (Fe-oxides, brass) and are enriched in mineral aggregates (quartz, feldspar, wollastonite, glass) or vaporized and condensed as chlorides or sulphates. Parameters controlling the mobilization of neutral and acidic fly ash leaching are pH and redox conditions, liquid to solid ratio, extraction time and temperature. Almost no depletion for Zn, Pb, Cu and Cd is achieved by performing neutral leaching. Acidic fly ash leaching results in depletion factors of 40% for Zn, 53% for Cd, 8% for Pb and 6% for Cu. The extraction of Pb and Cu are mainly limited due to a cementation process and the formation of a PbCu 0 -alloy-phase and to a minor degree due to secondary precipitation (PbCl 2 ). The addition of hydrogen peroxide during acidic fly ash leaching (optimized acidic leaching) prevents this reduction through oxidation of metallic components and thus significantly higher depletion factors for Pb (57%), Cu (30%) and Cd (92%) are achieved. The elevated metal depletion using acidic leaching in combination with hydrogen peroxide justifies the extra effort not only by reduced metal loads to the environment but also by reduced deposition costs. Copyright © 2016 Elsevier Ltd. All rights reserved.

Comparison of ultrasonic-assisted and regular leaching of germanium from by-product of zinc metallurgy.

PubMed

Zhang, Libo; Guo, Wenqian; Peng, Jinhui; Li, Jing; Lin, Guo; Yu, Xia

2016-07-01

A major source of germanium recovery and also the source of this research is the by-product of lead and zinc metallurgical process. The primary purpose of the research is to investigate the effects of ultrasonic assisted and regular methods on the leaching yield of germanium from roasted slag containing germanium. In the study, the HCl-CaCl2 mixed solution is adopted as the reacting system and the Ca(ClO)2 used as the oxidant. Through six single factor (leaching time, temperature, amount of Ca(ClO)2, acid concentration, concentration of CaCl2 solution, ultrasonic power) experiments and the comparison of the two methods, it is found the optimum collective of germanium for ultrasonic-assisted method is obtained at temperature 80 °C for a leaching duration of 40 min. The optimum concentration for hydrochloric acid, CaCl2 and oxidizing agent are identified to be 3.5 mol/L, 150 g/L and 58.33 g/L, respectively. In addition, 700 W is the best ultrasonic power and an over-high power is adverse in the leaching process. Under the optimum condition, the recovery of germanium could reach up to 92.7%. While, the optimum leaching condition for regular leaching method is same to ultrasonic-assisted method, except regular method consume 100 min and the leaching rate of Ge 88.35% is lower about 4.35%. All in all, the experiment manifests that the leaching time can be reduced by as much as 60% and the leaching rate of Ge can be increased by 3-5% with the application of ultrasonic tool, which is mainly thanks to the mechanical action of ultrasonic. Copyright © 2015 Elsevier B.V. All rights reserved.

Different low-molecular-mass organic acids specifically control leaching of arsenic and lead from contaminated soil

NASA Astrophysics Data System (ADS)

Ash, Christopher; Tejnecký, Václav; Borůvka, Luboš; Drábek, Ondřej

2016-04-01

Low-molecular-mass organic acids (LMMOA) are of key importance for mobilisation and fate of metals in soil, by functioning as ligands that increase the amount of dissolved metal in solution or by dissociation of metal binding minerals. Column leaching experiments were performed on soil polluted with As and Pb, in order to determine the specificity of LMMOA related release for individual elements, at varying organic acid concentrations. Acetic, citric and oxalic acids were applied in 12 h leaching experiments over a concentration range (0.5-25 mM) to soil samples that represent organic and mineral horizons. The leaching of As followed the order: oxalic > citric > acetic acid in both soils. Arsenic leaching was attributed primarily to ligand-enhanced dissolution of mineral oxides followed by As released into solution, as shown by significant correlation between oxalic and citric acids and content of Al and Fe in leaching solutions. Results suggest that subsurface mineral soil layers are more vulnerable to As toxicity. Leaching of Pb from both soils followed the order: citric > oxalic > acetic acid. Mineral soil samples were shown to be more susceptible to leaching of Pb than samples characterised by a high content of organic matter. The leaching efficiency of citric acid was attributed to formation of stable complexes with Pb ions, which other acids are not capable of. Results obtained in the study are evidence that the extent of As and Pb leaching in contaminated surface and subsurface soil depends significantly on the types of carboxylic acid involved. The implications of the type of acid and the specific element that can be mobilised become increasingly significant where LMMOA concentrations are highest, such as in rhizosphere soil.

A brief history of people and events related to atomic weapons testing in the Marshall Islands.

PubMed

Simon, S L

1997-07-01

The events related to nuclear testing in the Marshall Islands began at the end of WWII when the U.S. began an initiative to determine the effect of nuclear weapons on naval vessels and on the performance of military personnel. The first tests took place in 1946 even though the area known as Micronesia was not entrusted to the U.S. by the United Nations until 1947. Beginning with the first relocation of the Bikini people to Rongerik Atoll in 1946, the saga of the Marshall Islands involvement in the atomic age began. Although the testing program was limited to the years 1946 through 1958, many of the consequences and events related to the testing program continued over the decades since. That story is still ongoing with programs currently underway to attempt to resettle previously displaced communities, remediate contaminated islands, and to settle claims of damages to individuals and communities. The history of the years subsequent to 1958 are a mixed chronicle of a few original scientific investigations aimed at understanding the coral atoll environment, continued surveillance of the acutely exposed Marshallese, some efforts at cleanup and remediation, numerous monitoring programs and many studies repeated either for credibility purposes, to satisfy international demands or because the changing state of knowledge of radiation protection has necessitated us to rethink earlier beliefs and conclusions about late health effects and social consequences. The objective of this paper is to briefly note many of the historical and political events, scientific studies, persons and publications from 1946 to the present that relate to atomic weapons testing in the Marshall Islands.

Relations of Water Quality to Agricultural Chemical Use and Environmental Setting at Various Scales - Results from Selected Studies of the National Water-Quality Assessment Program

USGS Publications Warehouse

,

2008-01-01

In 1991, the U.S. Geological Survey (USGS) began studies of 51 major river basins and aquifers across the United States as part of the National Water-Quality Assessment (NAWQA) Program to provide scientifically sound information for managing the Nation's water resources. The major goals of the NAWQA Program are to assess the status and long-term trends of the Nation's surface- and ground-water quality and to understand the natural and human factors that affect it (Gilliom and others, 1995). In 2001, the NAWQA Program began a second decade of intensive water-quality assessments. The 42 study units for this second decade were selected to represent a wide range of important hydrologic environments and potential contaminant sources. These NAWQA studies continue to address the goals of the first decade of the assessments to determine how water-quality conditions are changing over time. In addition to local- and regional-scale studies, NAWQA began to analyze and synthesize water-quality status and trends at the principal aquifer and major river-basin scales. This fact sheet summarizes results from four NAWQA studies that relate water quality to agricultural chemical use and environmental setting at these various scales: * Comparison of ground-water quality in northern and southern High Plains agricultural settings (principal aquifer scale); * Distribution patterns of pesticides and degradates in rain (local scale); * Occurrence of pesticides in shallow ground water underlying four agricultural areas (local and regional scales); and * Trends in nutrients and sediment over time in the Missouri River and its tributaries (major river-basin scale).

Development and Implementation of a Comprehensive Risk Management Program at the USAF Academy Hospital.

DTIC Science & Technology

1980-04-01

much less con - cerned about malpractice problems. As a result of the program, they began to view the risk management program as their own and to recog...that con - tributes to better patient care. 131 Implementing Risk Management According to Donovan and Bader, an action plan for the systems approach might...Al87 344 DEVELOPMENT AND IMPLEMENTATION OF A COMPREHENSIVE RISK 1 MANAGEMENT PROGRAM AT THE USAF ACADEMY HOSPITAL(U) ARMY HEALTH CARE STUDIES AND

40 CFR 230.72 - Actions controlling the material after discharge.

Code of Federal Regulations, 2010 CFR

2010-07-01

... and disposal sites where the potential for erosion, slumping or leaching of materials into the... containment areas to reduce leaching where leaching of chemical constituents from the discharged material is...

40 CFR 230.72 - Actions controlling the material after discharge.

Code of Federal Regulations, 2013 CFR

2013-07-01

... and disposal sites where the potential for erosion, slumping or leaching of materials into the... containment areas to reduce leaching where leaching of chemical constituents from the discharged material is...

40 CFR 230.72 - Actions controlling the material after discharge.

Code of Federal Regulations, 2011 CFR

2011-07-01

... and disposal sites where the potential for erosion, slumping or leaching of materials into the... containment areas to reduce leaching where leaching of chemical constituents from the discharged material is...

40 CFR 230.72 - Actions controlling the material after discharge.

Code of Federal Regulations, 2012 CFR

2012-07-01

... and disposal sites where the potential for erosion, slumping or leaching of materials into the... containment areas to reduce leaching where leaching of chemical constituents from the discharged material is...

40 CFR 230.72 - Actions controlling the material after discharge.

Code of Federal Regulations, 2014 CFR

2014-07-01

... and disposal sites where the potential for erosion, slumping or leaching of materials into the... containment areas to reduce leaching where leaching of chemical constituents from the discharged material is...

Leaching of manganese from electrolytic manganese residue by electro-reduction.

PubMed

Shu, Jiancheng; Liu, Renlong; Liu, Zuohua; Chen, Hongliang; Tao, Changyuan

2017-08-01

In this study, an improved process for leaching manganese from electrolytic manganese residue (EMR) by electro-reduction was developed. The mechanisms of the electro-reduction leaching were investigated through X-ray diffraction, scanning electron microscopy, X-ray fluorescence, and Brunauer Emmett Teller. The results show that the electric field could change the surface charge distribution of EMR particles, and the high-valent manganese can be reduced by electric field. The leaching efficient of manganese reached 84.1% under the optimal leaching condition: 9.2 wt% H 2 SO 4 , current density of 25 mA/cm 2 , solid-to-liquid ratio of 1:5, and leaching time for 1 h. It is 37.9% higher than that attained without an electric field. Meanwhile, the manganese content in EMR decreased from 2.57% to 0.48%.

Dynamics analysis of extraction of manganese intensified by electric field

NASA Astrophysics Data System (ADS)

Ma, Wenrui; Tao, Changyuan; Li, Huizhan; Liu, Zuohua; Liu, Renlong

2018-06-01

In this study, a process reinforcement technology for leaching process of pyrolusite was developed. The electric field was introduced to decrease reaction temperature and improve the leaching rate of pyrolusite. The mechanisms of electric field intensifying leaching process of pyrolusite were investigated through X-ray diffraction (XRD), and Brunauer Emmett Teller (BET) in detail. The results showed that the electric field could decrease obviously the apparent activation energy of leaching process of pyrolusite. The apparent activation energy of the leaching of pyrolusite intensified by electric field was calculated to be 53.76 kJ.mol-1. In addition, the leaching efficiency of manganese was effectively increased by 10% to 20% than that without electric field under the same conditions. This was because that the electron conduit between Fe (II)/Fe (III) and pyrite was dredged effectively by electric field.

Recovery of Precious and Base Metals from Waste Printed Circuit Boards Using a Sequential Leaching Procedure

NASA Astrophysics Data System (ADS)

Batnasan, Altansukh; Haga, Kazutoshi; Shibayama, Atsushi

2018-02-01

This paper considers the issue of recycling of waste printed circuit boards (WPCBs) containing precious and base metals in appreciable amounts. High-pressure oxidative leaching (HPOL) with dilute sulfuric acid resulted in removal of a significant amount of base metals from a WPCB ash sample obtained by incineration at 800°C. The parameters investigated in the precious metal leaching from WPCB residue after HPOL included the sulfuric acid concentration, thiourea concentration, oxidant concentration, leaching temperature, and leaching time. Recovery of gold, silver, and palladium of 100%, 81%, and 13% from the WPCB residue sample was achieved by thiourea leaching under optimized conditions. The results show that the efficiency of precious metal dissolution from the WPCB sample using thiourea solution depended strongly on the concentration of both thiourea and oxidant.

Recovery of Precious and Base Metals from Waste Printed Circuit Boards Using a Sequential Leaching Procedure

NASA Astrophysics Data System (ADS)

Batnasan, Altansukh; Haga, Kazutoshi; Shibayama, Atsushi

2017-12-01

This paper considers the issue of recycling of waste printed circuit boards (WPCBs) containing precious and base metals in appreciable amounts. High-pressure oxidative leaching (HPOL) with dilute sulfuric acid resulted in removal of a significant amount of base metals from a WPCB ash sample obtained by incineration at 800°C. The parameters investigated in the precious metal leaching from WPCB residue after HPOL included the sulfuric acid concentration, thiourea concentration, oxidant concentration, leaching temperature, and leaching time. Recovery of gold, silver, and palladium of 100%, 81%, and 13% from the WPCB residue sample was achieved by thiourea leaching under optimized conditions. The results show that the efficiency of precious metal dissolution from the WPCB sample using thiourea solution depended strongly on the concentration of both thiourea and oxidant.

Leaching of Chalcopyrite with Thiobacillus ferrooxidans: Effect of Surfactants and Shaking

PubMed Central

Duncan, D. W.; Trussell, P. C.; Walden, C. C.

1964-01-01

The rate of leaching of chalcopyrite by Thiobacillus ferrooxidans has been greatly accelerated by using shaken flasks in place of stationary bottles or percolators. A further increase in rate and extent of leaching was obtained by the use of Tween 20, 40, 60, and 80, Triton X-100, Quaker TT 5386, and Hyamine 2389. Tween 20 was the most effective surfactant. No individual component of the Tween molecule was responsible for the improved leaching. The Tween-to-chalcopyrite ratio is more important than the Tween-to-medium ratio. The effect of the surfactants is probably due to increased contact between the mineral surface and the organism, and shaking provides the necessary oxygen. Rates and yields obtained by use of surfactants and shaking as aids to microbiological leaching approach those obtained with acidified erric sulfate leaching. PMID:14131359

Evaluation of the leaching behavior of incineration bottom ash using seawater: A comparison with standard leaching tests.

PubMed

Lin, Wenlin Yvonne; Heng, Kim Soon; Nguyen, Minh Quan; Ho, Jin Rui Ivan; Mohamed Noh, Omar Ahmad Bin; Zhou, Xue Dong; Liu, Alec; Ren, Fei; Wang, Jing-Yuan

2017-04-01

Batch and column tests were conducted on untreated incineration bottom ash (IBA) samples from two incineration plants in Singapore, using seawater as the leachant. The main objective of this study was to investigate the change in the leaching behavior of certain elements (i.e. As, Cd, Cr, Cu, Ni, Pb, Sb, Se and Zn) when IBA comes into contact with seawater. Such an investigation using seawater as leachant was not commonly carried out when investigating leaching behavior in IBA. The leaching tests were then carried out on the same IBA samples using DI water, as a comparison. Lower level of leaching was observed for Pb and Zn when seawater was used as the leachant. Cr and Sb showed significant cumulative release at Liquid-to-Solids (L/S) ratio 5 in the seawater column leaching. The influence of Dissolved Organic Carbon (DOC) on Cu leaching seems to decrease after L/S 2 when using seawater in the column test. Although the leaching behavior of IBA was affected when seawater was used, for the column test, there was no significant difference during the initial release when compared to DI water. The initial L/S fractions collected were important as the low L/S ratios represent the pore water concentration and the maximum output in an actual application. The results from this study would be useful for the future study on using IBA in marine applications. Copyright © 2016 Elsevier Ltd. All rights reserved.

A green salt-leaching technique to produce sericin/PVA/glycerin scaffolds with distinguished characteristics for wound-dressing applications.

PubMed

Aramwit, Pornanong; Ratanavaraporn, Juthamas; Ekgasit, Sanong; Tongsakul, Duangta; Bang, Nipaporn

2015-05-01

Sericin/PVA/glycerin scaffolds could be fabricated using the freeze-drying technique; they showed good physical and biological properties and can be applied as wound dressings. However, freeze-drying is an energy- and time-consuming process with a high associated cost. In this study, an alternative, solvent-free, energy- and time-saving, low-cost salt-leaching technique is introduced as a green technology to produce sericin/PVA/glycerin scaffolds. We found that sericin/PVA/glycerin scaffolds were successfully fabricated without any crosslinking using a salt-leaching technique. The salt-leached sericin/PVA/glycerin scaffolds had a porous structure with pore interconnectivity. The sericin in the salt-leached scaffolds had a crystallinity that was as high as that of the freeze-dried scaffolds. Compared to the freeze-dried scaffolds with the same composition, the salt-leached sericin/PVA/glycerin scaffolds has larger pores, a lower Young's modulus, and faster rates of biodegradation and sericin release. When cultured with L929 mouse fibroblast cells, a higher number of cells were found in the salt-leached scaffolds. Furthermore, the salt-leached scaffolds were less adhesive to the wound, which would reduce pain upon removal. Therefore, salt-leached sericin/PVA/glycerin scaffolds with distinguished characteristics were introduced as another choice of wound dressing, and their production process was simpler, more energy efficient, and saved time and money compared to the freeze-dried scaffolds. © 2014 Wiley Periodicals, Inc.

[Remediation of Cu-Pb-contaminated loess soil by leaching with chelating agent and biosurfactant].

PubMed

Liu, Xia; Wang, Jian-Tao; Zhang, Meng; Wang, Li; Yang, Ya-Ti

2013-04-01

Because of its strong chelation, solubilization characteristics, the chelating agents and biosurfactant are widely used in remediation of heavy metals and organic contaminated soils. Ethylenediamine tetraacetic acid (EDTA), citric acid (CIT) and dirhamnolipid (RL2) were selected as the eluent. Batch experiments and column experiments were conducted to investigate the leaching effect of the three kinds of eluent, as well as the mixture of biosurfactant and chelating agent for Cu, Pb contaminated loess soil. The results showed that the leaching efficiencies of different eluent on Cu, Pb contaminated loess soil followed the sequence of EDTA > CIT > RL2. At an eluent concentration of 0.02 mol x L(-1), the Cu leaching efficiency was 62.74% (EDTA), 52.28% (CIT) and 15.35% (RL2), respectively; the Pb leaching efficiency was 96.10% (EDTA), 23.08% (CIT) and 14.42% (RL2), respectively. When the concentration of RL2 was 100 CMC, it had synergistic effects on the other two kinds of chelating agent in Cu leaching, and when the concentration of RL2 was 200 CMC, it had antagonism effects. The effect of RL2 on EDTA in Pb leaching was similar to that in Cu leaching. Pb leaching by CIT was inhibited in the presence of RL2. EDTA and CIT could effectively remove Cu and Pb in exchangeable states, adsorption states, carbonate salts and organic bound forms; RL2 could effectively remove Cu and Pb in exchangeable and adsorbed states.

SANSMIC Validation.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weber, Paula D.; Rudeen, David Keith; Lord, David L.

2014-08-01

SANSMIC is solution mining software that was developed and utilized by SNL in its role as geotechnical advisor to the US DOE SPR for planning purposes. Three SANSMIC leach modes - withdrawal, direct, and reverse leach - have been revalidated with multiple test cases for each mode. The withdrawal mode was validated using high quality data from recent leach activity while the direct and reverse modes utilized data from historical cavern completion reports. Withdrawal results compared very well with observed data, including the location and size of shelves due to string breaks with relative leached volume differences ranging from 6more » - 10% and relative radius differences from 1.5 - 3%. Profile comparisons for the direct mode were very good with relative leached volume differences ranging from 6 - 12% and relative radius differences from 5 - 7%. First, second, and third reverse configurations were simulated in order to validate SANSMIC over a range of relative hanging string and OBI locations. The first-reverse was simulated reasonably well with relative leached volume differences ranging from 1 - 9% and relative radius differences from 5 - 12%. The second-reverse mode showed the largest discrepancies in leach profile. Leached volume differences ranged from 8 - 12% and relative radius differences from 1 - 10%. In the third-reverse, relative leached volume differences ranged from 10 - 13% and relative radius differences were %7E4 %. Comparisons to historical reports were quite good, indicating that SANSMIC is essentially the same as documented and validated in the early 1980's.« less

Copper leaching of MSWI bottom ash co-disposed with refuse: effect of short-term accelerated weathering.

PubMed

Su, Lianghu; Guo, Guangzhai; Shi, Xinlong; Zuo, Minyu; Niu, Dongjie; Zhao, Aihua; Zhao, Youcai

2013-06-01

Co-disposal of refuse with municipal solid waste incinerator (MSWI) bottom ash (IBA) either multi-layered as landfill cover or mixed with refuse could pose additional risk to the environment because of enhanced leaching of heavy metals, especially Cu. This study applied short-term accelerated weathering to IBA, and monitored the mineralogical and chemical properties of IBA during the weathering process. Cu extractability of the weathered IBA was then evaluated using standard leaching protocols (i.e. SPLP and TCLP) and co-disposal leaching procedure. The results showed that weathering had little or no beneficial effect on Cu leaching in SPLP and TCLP, which can be explained by the adsorption and complexation of Cu with DOM. However, the Cu leaching of weathered IBA was reduced significantly when situated in fresh simulated landfill leachate. This was attributed to weakening Cu complexation with fulvic acid or hydrophilic fractions and/or intensifying Cu absorption to neoformed hydr(oxide) minerals in weathered IBA. The amount of total leaching Cu and Cu in free or labile complex fraction (the fraction with the highest mobility and bio-toxicity) of the 408-h weathered IBA were remarkably decreased by 86.3% and 97.6% in the 15-day co-disposal leaching test. Accelerated weathering of IBA may be an effective pretreatment method to decrease Cu leaching prior to its co-disposal with refuse. Copyright © 2013 Elsevier Ltd. All rights reserved.

Increasing the number of trained health and safety professionals in agricultural medicine: evaluation of the "building capacity" program, 2007-2013.

PubMed

Rudolphi, Josie M; Donham, Kelley J

2015-01-01

ABSTRACT The University of Iowa began training health care professionals to care for farmers' occupational health needs since 1974. In order to geographically expand this training to practicing health and safety professionals, the "Building Capacity: A National Resource of Agricultural Medicine Professionals" program was developed and launched in 2006. The model began in 1987 as a program of Iowa's Center for Agricultural Safety and Health. In 2006, with funding from the National Institute for Occupational Safety and Health (NIOSH), Great Plains Center for Agricultural Health (GPCAH), the program was expanded beyond the Iowa borders. The principal component of the program, the 40-hour course, Agricultural Medicine: Occupational and Environmental Health for Rural Health Professionals-the Core Course (AMCC) is now being offered to health and safety professionals in nine states in the United States, in Australia, and a modified version presented in Turkey. An initial paper evaluated the first phase of the program, years 2007-2010. This paper compares the first phase (2007-2010) with the second phase (2011-2013), which has involved over 500 health and safety professionals. This paper also describes evaluation of the course and changes resulting from the evaluation. Finally, this paper describes best practices for operating this program and makes recommendations for future courses, as well as other trainings within the field.

National Water-Quality Assessment Program: The Sacramento River Basin

USGS Publications Warehouse

Domagalski, Joseph L.; Brown, Larry R.

1994-01-01

In 1991, the U.S. Geological Survey (USGS) began to implement a full-scale National Water-Quality Assessment (NAWQA) program. The long-term goals of the NAWQA program are to describe the status of and trends in the quality of a large, representative part of the Nation's surface- and ground-water resources and to identify the major natural and human factors that affect the quality of those resources. In addressing these goals, the program will provide a wealth of water- quality information that will be useful to policy makers and managers at the national, State, and local levels. A major asset of the NAWQA program is that it will allow for the integration of water-quality information collected at several scales. A major component of the program is the study-unit investigation-the foundation of national- level assessment. The 60 study units of the NAWQA program are hydrologic systems that include parts of most major river basins and aquifer systems of the conterminous United States. These study units cover areas of 1,000 to more than 60,000 square miles and represent 60 to 70 percent of the Nation's water use and population served by public water supplies. Investigations of the first 20 study units began in 1991. In 1994, the Sacramento River Basin was among the second set of 20 NAWQA study units selected for investigation.

Residency Programs' Evaluations of the Competencies: Data Provided to the ACGME About Types of Assessments Used by Programs

PubMed Central

Holt, Kathleen D.; Miller, Rebecca S.; Nasca, Thomas J.

2010-01-01

Background In 1999, the Accreditation Council for Graduate Medical Education (ACGME) Outcome Project began to focus on resident performance in the 6 competencies of patient care, medical knowledge, professionalism, practice-based learning and improvement, interpersonal communication skills, and professionalism. Beginning in 2007, the ACGME began collecting information on how programs assess these competencies. This report provides information on the nature and extent of those assessments. Methods Using data collected by the ACGME for site visits, we use descriptive statistics and percentages to describe the number and type of methods and assessors accredited programs (n  =  4417) report using to assess the competencies. Observed differences among specialties, methodologies, and assessors are tested with analysis of variance procedures. Results Almost all (>97%) of programs report assessing all of the competencies and using multiple methods and multiple assessors. Similar assessment methods and evaluator types were consistently used across the 6 competencies. However, there were some differences in the use of patient and family as assessors: Primary care and ambulatory specialties used these to a greater extent than other specialties. Conclusion Residency programs are emphasizing the competencies in their evaluation of residents. Understanding the scope of evaluation methodologies that programs use in resident assessment is important for both the profession and the public, so that together we may monitor continuing improvement in US graduate medical education. PMID:22132294

Horse paddocks - an emerging source of agricultural water pollution

NASA Astrophysics Data System (ADS)

Masud Parvage, Mohammed; Ulén, Barbro; Kirchmann, Holger

2015-04-01

Horse farms occupy about 4% of the total agricultural land in the EU but are not well investigated with regard to their impact on water quality. Horse paddocks commonly hold horses on a limited space and the animal density often exceeds the recommended density. Therefore, paddock soils receive significant amounts of phosphorus (P) and nitrogen (N) through feed residues and deposition of faeces and urine, which can lead to nutrient build-up in the soil and subsequent losses to aquatic systems. This study characterized the potential risk of phosphorus (P) and nitrogen (N) leaching losses from Swedish horse paddocks through three stage examination of soil and water P and N status. The experiment began with a pilot study where surface soil P status and eight years of drainage P data were examined from a paddock catchment and an adjacent arable catchment both receiving similar amount of P and N over years. Results showed that there were no signi?cant differences in water-soluble P (WSP) or total P data in soils but the drainage water P concentrations, being higher in the paddock catchment (0.33 mg P l-1, mainly in dissolved reactive form) than the arable catchment (0.10 mg P l-1). In the second experiment, soil P and N status were examined in different parts of horse paddocks (feeding, grazing, and excretion areas) to identify existence of any potential hotspots for losses within the paddock. In total, seven horse farms, covering different grazing densities and soil textures representative of Swedish horse paddocks were examined. The results showed that concentrations of WSP, plant available P or P-AL (P extracted in ammonium acetate lactate solution at pH 3.75), and total N were highest in feeding and excretion areas within the paddocks. It was also observed that the WSP concentration in the paddocks was strongly correlated with horse density (R2 = 0.80, p < 0.001) and P-AL with years of paddock management (R2 = 0.78, p < 0.001). In the final experiment, topsoil columns (0-20 cm) from the different segments of the paddock were isolated and potential leaching losses of P, N and carbon (C) were measured from two representative horse paddock (a clay and a loamy sand) following simulated rainfall events in the laboratory. Results showed that the leachate concentrations and net release of P, N, and dissolved organic C (DOC) from paddock topsoils were highest in feeding and excretion areas and considerably higher from the loamy sand than the clay paddock topsoil. It was concluded that: i) horse paddocks pose a potential threat to water quality via leaching of excess P and N, ii) feeding and excretion areas are potential hotspots for highly enhanced leaching losses, and iii) paddocks established on sandy soils are particularly susceptible to high losses.

Idaho Nuclear Technology and Engineering Center Low-Activity Waste Process Technology Program, FY-98 Status Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Herbst, A.K.; Rogers, A.Z.; McCray, J.A.

The Low-Activity Waste Process Technology Program at the Idaho Nuclear Technology and Engineering Center (INTEC) anticipates that large volumes of low-level/low-activity wastes will need to be grouted prior to near-surface disposal. During fiscal year 1998, three grout formulations were studied for low-activity wastes derived from INTEC liquid sodium-bearing waste. Compressive strength and leach results are presented for phosphate bonding cement, acidic grout, and alkaline grout formulations. In an additional study, grout formulations are recommended for stabilization of the INTEC underground storage tank residual heels.

Evaluation of the Effectiveness of the Defense Systems Acquisition Review Council (DSARC). Volume I. Technical Report with Appendices A and B.

DTIC Science & Technology

1983-04-04

Roland 11 Perry Nelson* Hacker Murray 6/79 NAVSTAR 11 Dineen’ Shorey’ Hessler’ Murray 11/79 Copperhead 11 LaBerge * Pinie Wacker Murray 1/SO FYS III... LaBerge ’ Danzig’ Uarshman’ Christie’* 10/80 FVS PR LaBerge ’ Danzig* Bting Cua 6/82 LAMPS III Wade* Leach’ Heth h % Not a principal. "no appointee, actg...to illustrate the situation: FVS Program Review 1/80 LaBerge *Danzig* Harshman*Christie* Program Review 10/80 LaBerge *Danzig* Borsting Murray TRIDENT

Laboratory studies of CCA-C leaching : influence of wood and soil properties on extent of arsenic and copper depletion.

Treesearch

Doug Crawford; Roger Fox; Pascal Kamden; Stan Lebow; Darrel Nicholas; David Pettry; Tor Schultz; Linda Sites; Richard Ziobro

2002-01-01

The extent which a wood preservative leaches is important for efficacy studies and environmental concerns. However, little information exists on the effect soil properties have on leaching. This study investigated leaching of stakelets which had been cut from five different southern yellow pine (SYP) sapwood boards then treated with CCA-C to a target retention of 6.4...

Leaching variations of heavy metals in chelator-assisted phytoextraction by Zea mays L. exposed to acid rainfall.

PubMed

Lu, Yayin; Luo, Dinggui; Liu, Lirong; Tan, Zicong; Lai, An; Liu, Guowei; Li, Junhui; Long, Jianyou; Huang, Xuexia; Chen, Yongheng

2017-11-01

Chelant-enhanced phytoextraction method has been put forward as an effective soil remediation method, whereas the heavy metal leaching could not be ignored. In this study, a cropping-leaching experiment, using soil columns, was applied to study the metal leaching variations during assisted phytoextraction of Cd- and Pb-polluted soils, using seedlings of Zea mays, applying three different chelators (EDTA, EDDS, and rhamnolipid), and artificial rainfall (acid rainfall or normal rainfall). It showed that artificial rainfall, especially artificial acid rain, after chelator application led to the increase of heavy metals in the leaching solution. EDTA increased both Cd and Pb concentrations in the leaching solution, obviously, whereas EDDS and rhamnolipid increased Cd concentration but not Pb. The amount of Cd and Pb decreased as the leaching solution increased, the patterns as well matched LRMs (linear regression models), with R-square (R 2 ) higher than 90 and 82% for Cd and Pb, respectively. The maximum cumulative Cd and Pb in the leaching solutions were 18.44 and 16.68%, respectively, which was amended by EDTA and acid rainwater (pH 4.5), and followed by EDDS (pH 4.5), EDDS (pH 6.5), rhamnolipid (0.5 g kg -1 soil, pH 4.5), and rhamnolipid (pH 6.5).

Effect of ferrous sulfate and nitrohumic acid neutralization on the leaching of metals from a combined bauxite residue.

PubMed

Ren, Jie; Liu, Jidong; Chen, Juan; Liu, Xiaolian; Li, Fasheng; Du, Ping

2017-04-01

Bauxite residue neutralization is intended to open opportunities for revegetation and reuse of the residue. Ferrous sulfate (FS) and nitrohumic acid (NA) were two kinds of materials studied for pH reduction of the residue from 10.6 to 8.3 and 8.1, respectively. The effects of FS and NA on the leaching of metals from a combined bauxite residue were investigated by using sequential and multiple extraction procedures. Neutralization with FS and NA restricted the leaching of Al, V, and Pb from the residue but promoted the leaching of Fe, Cu, Mn, and Ni, consistent with the changes in the potentially mobile fractions. With the exceptions of Pb and Ni, leaching of metals increased during a 10-day extraction period. However, the maximum leaching of Al, V, Pb, Fe, Cu, Mn, and Ni from neutralized bauxite residue were 0.46 mg/L, 59.3, 12.9, 167, 95.3, 15.5, and 14.5 μg/L, respectively, which were under the corresponding limits in the National Standard (GB/T 14848-93). Although it is necessary to consider the continued leaching of metals during neutralization, both maximum and accumulation leaching concentrations of metals from a combined bauxite residue were too low to pose a potential environmental risk.

Leaching kinetics of bottom ash waste as a source of calcium ions.

PubMed

Koech, Lawrence; Everson, Ray; Neomagus, Hein; Rutto, Hilary

2015-02-01

Bottom ash is a waste material from coal-fired power plants, and it is known to contain elements that are potentially toxic at high concentration levels when disposed in landfills. This study investigates the use of bottom ash as a partial substitute sorbent for wet flue gas desulfurization (FGD) processes by focusing on its leaching kinetics in adipic acid. This was studied basing on the shrinking core model that was applied to the experimental data obtained by the authors presented at the International Conference on Industrial, Manufacturing, Automation and Mechanical Engineering, Johannesburg, South Africa, November 27-28, 2013) on dissolution of bottom ash. The leaching rate constant was obtained from different reaction variables, namely, temperature, pH, acid concentration, and solid-to-liquid ratio, that could affect the leaching process. The solid sample of bottom ash was characterized at different leaching periods using X-ray diffraction (XRD) and scanning electron microscopy (SEM). It was found that solid-to-liquid ratio had a significant effect on the leaching rate constant when compared with other variables. The leaching kinetics showed that diffusion through the product layer was the rate-controlling step during leaching, and the activation energy for the process was found to be 18.92 kJ/mol.

In Vitro Studies Evaluating Leaching of Mercury from Mine Waste Calcine Using Simulated Human Body Fluids

PubMed Central

2010-01-01

In vitro bioaccessibility (IVBA) studies were carried out on samples of mercury (Hg) mine-waste calcine (roasted Hg ore) by leaching with simulated human body fluids. The objective was to estimate potential human exposure to Hg due to inhalation of airborne calcine particulates and hand-to-mouth ingestion of Hg-bearing calcines. Mine waste calcines collected from Hg mines at Almadén, Spain, and Terlingua, Texas, contain Hg sulfide, elemental Hg, and soluble Hg compounds, which constitute primary ore or compounds formed during Hg retorting. Elevated leachate Hg concentrations were found during calcine leaching using a simulated gastric fluid (as much as 6200 μg of Hg leached/g sample). Elevated Hg concentrations were also found in calcine leachates using a simulated lung fluid (as much as 9200 μg of Hg leached/g), serum-based fluid (as much as 1600 μg of Hg leached/g), and water of pH 5 (as much as 880 μg of Hg leached/g). The leaching capacity of Hg is controlled by calcine mineralogy; thus, calcines containing soluble Hg compounds contain higher leachate Hg concentrations. Results indicate that ingestion or inhalation of Hg mine-waste calcine may lead to increased Hg concentrations in the human body, especially through the ingestion pathway. PMID:20491469

In vitro studies evaluating leaching of mercury from mine waste calcine using simulated human body fluids.

PubMed

Gray, John E; Plumlee, Geoffrey S; Morman, Suzette A; Higueras, Pablo L; Crock, James G; Lowers, Heather A; Witten, Mark L

2010-06-15

In vitro bioaccessibility (IVBA) studies were carried out on samples of mercury (Hg) mine-waste calcine (roasted Hg ore) by leaching with simulated human body fluids. The objective was to estimate potential human exposure to Hg due to inhalation of airborne calcine particulates and hand-to-mouth ingestion of Hg-bearing calcines. Mine waste calcines collected from Hg mines at Almaden, Spain, and Terlingua, Texas, contain Hg sulfide, elemental Hg, and soluble Hg compounds, which constitute primary ore or compounds formed during Hg retorting. Elevated leachate Hg concentrations were found during calcine leaching using a simulated gastric fluid (as much as 6200 microg of Hg leached/g sample). Elevated Hg concentrations were also found in calcine leachates using a simulated lung fluid (as much as 9200 microg of Hg leached/g), serum-based fluid (as much as 1600 microg of Hg leached/g), and water of pH 5 (as much as 880 microg of Hg leached/g). The leaching capacity of Hg is controlled by calcine mineralogy; thus, calcines containing soluble Hg compounds contain higher leachate Hg concentrations. Results indicate that ingestion or inhalation of Hg mine-waste calcine may lead to increased Hg concentrations in the human body, especially through the ingestion pathway.

Aminocyclopyrachlor sorption-desorption and leaching from three Brazilian soils.

PubMed

Francisco, Jeane G; Mendes, Kassio F; Pimpinato, Rodrigo F; Tornisielo, Valdemar L; Guimarães, Ana C D

2017-07-03

This study aimed to evaluate the sorption-desorption and leaching of aminocyclopyrachlor from three Brazilian soils. The sorption-desorption of 14 C-aminocyclopyrachlor was evaluated using the batch method and leaching was assessed in glass columns. The Freundlich model showed an adequate fit for the sorption-desorption of aminocyclopyrachlor. The Freundlich sorption coefficient [K f (sorption) ] ranged from 0.37 to 1.34 µmol (1-1/n) L 1/n kg -1 and showed a significant positive correlation with the clay content of the soil, while the K f (desorption) ranged from 3.62 to 5.36 µmol (1-1/n) L 1/n kg -1 . The K f (desorption) values were higher than their respective K f (sorption) , indicating that aminocyclopyrachlor sorption is reversible, and the fate of this herbicide in the environment can be affected by leaching. Aminocyclopyrachlor was detected at all depths (0-30 cm) in all the studied soils, where leaching was influenced by soil texture. The total herbicide leaching from the sandy clay and clay soils was <0.06%, whereas, ∼3% leached from the loamy sand soil. The results suggest that aminocyclopyrachlor has a high potential of leaching, based on its low sorption and high desorption capacities. Therefore, this herbicide can easily contaminate underground water resources.

Leaching of Arsenic from Granular Ferric Hydroxide Residuals under Mature Landfill Conditions

PubMed Central

Ghosh, Amlan; Mukiibi, Muhammed; Sáez, A. Eduardo; Ela, Wendell P.

2008-01-01

Most arsenic bearing solid residuals (ABSR) from water treatment will be disposed in non-hazardous landfills. The lack of an appropriate leaching test to predict arsenic mobilization from ABSR creates a need to evaluate the magnitude and mechanisms of arsenic release under landfill conditions. This work studies the leaching of arsenic and iron from a common ABSR, granular ferric hydroxide, in a laboratory-scale column that simulates the biological and physicochemical conditions of a mature, mixed solid waste landfill. The column operated for approximately 900 days and the mode of transport as well as chemical speciation of iron and arsenic changed with column age. Both iron and arsenic were readily mobilized under the anaerobic, reducing conditions. During the early stages of operation, most arsenic and iron leaching (80% and 65%, respectively) was associated with suspended particulate matter and iron was lost proportionately faster than arsenic. In later stages, while the rate of iron leaching declined, the arsenic leaching rate increased greater than 7-fold. The final phase was characterized by dissolved species leaching. Future work on the development of standard batch leaching tests should take into account the dominant mobilization mechanisms identified in this work: solid associated transport, reductive sorbent dissolution, and microbially mediated arsenic reduction. PMID:17051802

Leaching of arsenic from granular ferric hydroxide residuals under mature landfill conditions.

PubMed

Ghosh, Amlan; Mukiibi, Muhammed; Sáez, A Eduardo; Ela, Wendell P

2006-10-01

Most arsenic bearing solid residuals (ABSR) from water treatment will be disposed in nonhazardous landfills. The lack of an appropriate leaching test to predict arsenic mobilization from ABSR creates a need to evaluate the magnitude and mechanisms of arsenic release under landfill conditions. This work studies the leaching of arsenic and iron from a common ABSR, granular ferric hydroxide, in a laboratory-scale column that simulates the biological and physicochemical conditions of a mature, mixed solid waste landfill. The column operated for approximately 900 days and the mode of transport as well as chemical speciation of iron and arsenic changed with column age. Both iron and arsenic were readily mobilized under the anaerobic, reducing conditions. During the early stages of operation, most arsenic and iron leaching (80% and 65%, respectively) was associated with suspended particulate matter, and iron was lost proportionately faster than arsenic. In later stages, while the rate of iron leaching declined, the arsenic leaching rate increased greater than 7-fold. The final phase was characterized by dissolved species leaching. Future work on the development of standard batch leaching tests should take into account the dominant mobilization mechanisms identified in this work: solid associated transport, reductive sorbent dissolution, and microbially mediated arsenic reduction.

Thiosulfate leaching of gold from waste mobile phones.

PubMed

Ha, Vinh Hung; Lee, Jae-chun; Jeong, Jinki; Hai, Huynh Trung; Jha, Manis K

2010-06-15

The present communication deals with the leaching of gold from the printed circuit boards (PCBs) of waste mobile phones using an effective and less hazardous system, i.e., a copper-ammonia-thiosulfate solution, as an alternative to the conventional and toxic cyanide leaching of gold. The influence of thiosulfate, ammonia and copper sulfate concentrations on the leaching of gold from PCBs of waste mobile phones was investigated. Gold extraction was found to be enhanced with solutions containing 15-20 mM cupric, 0.1-0.14 M thiosulfate, and 0.2-0.3 M ammonia. Similar trends were obtained for the leaching of gold from two different types of scraps and PCBs of waste mobile phones. From the scrap samples, 98% of the gold was leached out using a solution containing 20 mM copper, 0.12 M thiosulfate and 0.2 M ammonia. Similarly, the leaching of gold from the PCBs samples was also found to be good, but it was lower than that of scrap samples in similar experimental conditions. In this case, only 90% of the gold was leached, even with a contact time of 10h. The obtained data will be useful for the development of processes for the recycling of gold from waste mobile phones. Copyright 2010 Elsevier B.V. All rights reserved.

In vitro studies evaluating leaching of mercury from mine waste calcine using simulated human body fluids

USGS Publications Warehouse

Gray, John E.; Plumlee, Geoffrey S.; Morman, Suzette A.; Higueras, Pablo L.; Crock, James G.; Lowers, Heather A.; Witten, Mark L.

2010-01-01

In vitro bioaccessibility (IVBA) studies were carried out on samples of mercury (Hg) mine-waste calcine (roasted Hg ore) by leaching with simulated human body fluids. The objective was to estimate potential human exposure to Hg due to inhalation of airborne calcine particulates and hand-to-mouth ingestion of Hg-bearing calcines. Mine waste calcines collected from Hg mines at Almadén, Spain, and Terlingua, Texas, contain Hg sulfide, elemental Hg, and soluble Hg compounds, which constitute primary ore or compounds formed during Hg retorting. Elevated leachate Hg concentrations were found during calcine leaching using a simulated gastric fluid (as much as 6200 μg of Hg leached/g sample). Elevated Hg concentrations were also found in calcine leachates using a simulated lung fluid (as much as 9200 μg of Hg leached/g), serum-based fluid (as much as 1600 μg of Hg leached/g), and water of pH 5 (as much as 880 μg of Hg leached/g). The leaching capacity of Hg is controlled by calcine mineralogy; thus, calcines containing soluble Hg compounds contain higher leachate Hg concentrations. Results indicate that ingestion or inhalation of Hg mine-waste calcine may lead to increased Hg concentrations in the human body, especially through the ingestion pathway.

The mineralogical phase transformation of invisible gold-concentrate by microwave heating, and enhancement of their gold leaching rate

NASA Astrophysics Data System (ADS)

Bak, Geonyoung; Kim, Bongju; Choi, Nagchoul; Park*, Cheonyoung

2015-04-01

In this study, in order to obtain the maximum Au leaching rate, an invisible gold concentrate sample was microwave-treated and a thiourea leaching experiment was performed. It is found that gold exists as invisible as a result of observation with an optical microscope and an electron microscope. As the invisible gold concentrate sample was exposed to microwave longer, its temperature and weight loss were increased together and its S content was decreased. The conditions for the maximum Au leaching rate and the fast leaching effect were a particle size of -325×400 mesh, exposure to microwave for 70 minutes, 1.0 g of thiourea, 0.0504 g of sodium sulfite and 0.425 g of ferric sulfate. However, the condition under which Au was leached out to the maximum was applied to the control sample, but its Au leaching rate was just in a range of 78% to 88%. Such results suggest that the effect of sodium sulfite and ferric sulfate was more effective in the microwave-treated sample than in the control sample. Therefore, it was confirmed that the complete and very fast Au leaching can be achieved by means of the microwave pretreatment of invisible gold concentrate.

Comparison of mine waste assessment methods at the Rattler mine site, Virginia Canyon, Colorado

USGS Publications Warehouse

Hageman, Phil L.; Smith, Kathleen S.; Wildeman, Thomas R.; Ranville, James F.

2005-01-01

In a joint project, the mine waste-piles at the Rattler Mine near Idaho Springs, Colorado, were sampled and analyzed by scientists from the U.S. Geological Survey (USGS) and the Colorado School of Mines (CSM). Separate sample collection, sample leaching, and leachate analyses were performed by both groups and the results were compared. For the study, both groups used the USGS sampling procedure and the USGS Field Leach Test (FLT). The leachates generated from these tests were analyzed for a suite of elements using ICP-AES (CSM) and ICP-MS (USGS). Leachate geochemical fingerprints produced by the two groups for composites collected from the same mine waste showed good agreement. In another set of tests, CSM collected another set of Rattler mine waste composite samples using the USGS sampling procedure. This set of composite samples was leached using the Colorado Division of Minerals and Geology (CDMG) leach test, and a modified Toxicity Characteristic Leaching Procedure (TCLP) leach test. Leachate geochemical fingerprints produced using these tests showed a variation of more than a factor of two from the geochemical fingerprints produced using the USGS FLT leach test. We have concluded that the variation in the results is due to the different parameters of the leaching tests and not due to the sampling or analytical methods.

Should mandatory energy reporting be eliminated

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kendall, R.

1981-08-01

Energy users report problems with the Industrial Reporting Program (IRP), a joint voluntary energy-efficiency program which began in 1975. Since energy-intensive industries were already organizing voluntary reporting, the new program required unnecessary expenditures. The Reagan administration's plan to eliminate the program by not funding it is opposed by many energy managers who want the data collected to help them with their management programs. Their interest is primarily in a data base because energy costs provide adequate incentives to conserve. They also want interaction (preferably voluntary) between industry and goverment on efficiency-improvement opportunities. (DCK)

40 CFR 421.86 - Pretreatment standards for new sources.

Code of Federal Regulations, 2010 CFR

2010-07-01

... leached Cadmium .180 .072 Zinc .919 .378 (c) Subpart H—Leaching Wet Air Pollution Control. PSNS Pollutant... pounds) of zinc processed through leaching Cadmium .000 .000 Zinc .000 .000 (d) Subpart H—Electrolyte...

40 CFR 421.86 - Pretreatment standards for new sources.

Code of Federal Regulations, 2014 CFR

2014-07-01

... leached Cadmium .180 .072 Zinc .919 .378 (c) Subpart H—Leaching Wet Air Pollution Control. PSNS Pollutant... pounds) of zinc processed through leaching Cadmium .000 .000 Zinc .000 .000 (d) Subpart H—Electrolyte...

40 CFR 421.86 - Pretreatment standards for new sources.

Code of Federal Regulations, 2012 CFR

2012-07-01

... leached Cadmium .180 .072 Zinc .919 .378 (c) Subpart H—Leaching Wet Air Pollution Control. PSNS Pollutant... pounds) of zinc processed through leaching Cadmium .000 .000 Zinc .000 .000 (d) Subpart H—Electrolyte...

40 CFR 421.86 - Pretreatment standards for new sources.

Code of Federal Regulations, 2013 CFR

2013-07-01

... leached Cadmium .180 .072 Zinc .919 .378 (c) Subpart H—Leaching Wet Air Pollution Control. PSNS Pollutant... pounds) of zinc processed through leaching Cadmium .000 .000 Zinc .000 .000 (d) Subpart H—Electrolyte...

Evaluation of Michigan's engineering improvements for older drivers.

DOT National Transportation Integrated Search

2015-09-01

In 2004, the Michigan Department of Transportation (MDOT) began a comprehensive program : to implement engineering countermeasures to address the needs of older drivers. The : countermeasures included the use of Clearview Font on Guide Signs (freeway...

Pennsylvania safe routes to school program.

DOT National Transportation Integrated Search

2010-10-21

In October 2007, the Center for Nutrition and Activity promotion at Penn State Hershey Children's Hospital (Center) began working under contract with the Pennsylvania Deaprtment of Transportation )PennDOT) to develop, coordinate, and administer the n...

Effects of Leaching Behavior of Calcium Ions on Compression and Durability of Cement-Based Materials with Mineral Admixtures

PubMed Central

Cheng, An; Chao, Sao-Jeng; Lin, Wei-Ting

2013-01-01

Leaching of calcium ions increases the porosity of cement-based materials, consequently resulting in a negative effect on durability since it provides an entry for aggressive harmful ions, causing reinforcing steel corrosion. This study investigates the effects of leaching behavior of calcium ions on the compression and durability of cement-based materials. Since the parameters influencing the leaching behavior of cement-based materials are unclear and diverse, this paper focuses on the influence of added mineral admixtures (fly ash, slag and silica fume) on the leaching behavior of calcium ions regarding compression and durability of cemented-based materials. Ammonium nitrate solution was used to accelerate the leaching process in this study. Scanning electron microscopy, X-ray diffraction analysis, and thermogravimetric analysis were employed to analyze and compare the cement-based material compositions prior to and after calcium ion leaching. The experimental results show that the mineral admixtures reduce calcium hydroxide quantity and refine pore structure through pozzolanic reaction, thus enhancing the compressive strength and durability of cement-based materials. PMID:28809247

Antimony smelting process generating solid wastes and dust: characterization and leaching behaviors.

PubMed

Guo, Xuejun; Wang, Kunpeng; He, Mengchang; Liu, Ziwei; Yang, Hailin; Li, Sisi

2014-07-01

A large amount of solid waste has been produced by the antimony smelting process in the "World Capital of Antimony", Xikuangshan area in China. This study comprehensively investigated the physical and chemical characteristics of the various solid wastes, as well as the leaching behavior of the solid wastes, which included water-quenched slag, arsenic-alkali residue, desulfurized slag and blast furnace dust. These four types of waste were enriched in a variety of heavy metals and metalloids and more specifically with As and Sb levels up to 8.6 × 10⁴ and 3.16×10⁵ mg/kg, respectively, in arsenic-alkali residue. For desulfurized slag and water-quenched slag, the leaching concentration of Sb significantly exceeded the acceptable limits during the leaching tests using the toxicity characteristic leaching procedure and the synthetic precipitation leaching procedure. In addition, As leaching in arsenic-alkali residue was extraordinarily hazardous, being three orders of magnitude higher than the regulatory level of As. According to the results of the extraction tests, all the tested wastes were classified as hazardous waste. Copyright © 2014. Published by Elsevier B.V.

Study on the leaching behavior of actinides from nuclear fuel debris

NASA Astrophysics Data System (ADS)

Kirishima, Akira; Hirano, Masahiko; Akiyama, Daisuke; Sasaki, Takayuki; Sato, Nobuaki

2018-04-01

For the prediction of the leaching behavior of actinides contained in the nuclear fuel debris generated by the Fukushima Daiichi nuclear power plant accident in Japan, simulated fuel debris consisting of a UO2-ZrO2 solid solution doped with 137Cs, 237Np, 236Pu, and 241Am tracers was synthesized and investigated. The synthesis of the debris was carried out by heat treatment at 1200 °C at different oxygen partial pressures, and the samples were subsequently used for leaching tests with Milli-Q water and seawater. The results of the leaching tests indicate that the leaching of actinides depends on the redox conditions under which the debris was generated; for example, debris generated under oxidative conditions releases more actinide nuclides to water than that generated under reductive conditions. Furthermore, we found that, as Zr(IV) increasingly substituted U(IV) in the fluorite crystal structure of the debris, the actinide leaching from the debris decreased. In addition, we found that seawater leached more actinides from the debris than pure water, which seems to be caused by the complexation of actinides by carbonate ions in seawater.

Selection of organic acid leaching reagent for recovery of zinc and manganese from zinc-carbon and alkaline spent batteries

NASA Astrophysics Data System (ADS)

Yuliusman; Amiliana, R. A.; Wulandari, P. T.; Ramadhan, I. T.; Kusumadewi, F. A.

2018-03-01

Zinc-carbon and alkaline batteries are often used in electronic equipment that requires small quantities of power. The waste from these batteries contains valuable metals, such as zinc and manganese, that are needed in many industries and can pollute the environment if not treated properly. This paper concerns the recovery of zinc and manganese metals from zinc-carbon and alkaline spent batteries with leaching method and using organic acid as the environmental friendly leaching reagent. Three different organic acids, namely citric acid, malic acid and aspartic acid, were used as leaching reagents and compared with sulfuric acid as non-organic acid reagents that often used for leaching. The presence of hydrogen peroxide as manganese reducers was investigated for both organic and non-organic leaching reagents. The result showed that citric acid can recover 64.37% Zinc and 51.32% Manganese, while malic acid and aspartic acid could recover less than these. Hydrogen peroxide gave the significant effect for leaching manganese with non-organic acid, but not with organic acid.

Leaching lithium from the anode electrode materials of spent lithium-ion batteries by hydrochloric acid (HCl).

PubMed

Guo, Yang; Li, Feng; Zhu, Haochen; Li, Guangming; Huang, Juwen; He, Wenzhi

2016-05-01

Spent lithium-ion batteries (LIBs) are considered as an important secondary resource for its high contents of valuable components, such as lithium and cobalt. Currently, studies mainly focus on the recycling of cathode electrodes. There are few studies concentrating on the recovery of anode electrodes. In this work, based on the analysis result of high amount of lithium contained in the anode electrode, the acid leaching process was applied to recycle lithium from anode electrodes of spent LIBs. Hydrochloric acid was introduced as leaching reagent, and hydrogen peroxide as reducing agent. Within the range of experiment performed, hydrogen peroxide was found to have little effect on lithium leaching process. The highest leaching recovery of 99.4wt% Li was obtained at leaching temperature of 80°C, 3M hydrochloric acid and S/L ratio of 1:50g/ml for 90min. The graphite configuration with a better crystal structure obtained after the leaching process can also be recycled. Copyright © 2015 Elsevier Ltd. All rights reserved.

Leaching Behavior of Selected Trace and Toxic Metals in Coal Fly Ash Samples Collected from Two Thermal Power Plants, India.

PubMed

Sandeep, P; Sahu, S K; Kothai, P; Pandit, G G

2016-09-01

Studies on leaching behavior of metals associated with coal fly ash (FA) are of great concern because of possible contamination of the aquatic environment. In the present study, leaching behavior of metals (As, Se, Cr, Pb, V, Zn, etc.) in two different FA samples (FA1 and FA2) was investigated at various pH (2-12), temperatures of leachate solution and using TCLP. At pH 2, the highest leaching was observed for Fe (21.6 and 32.8 µg/g), whereas at pH 12, Arsenic was found to have the highest leaching (1.5 and 2.4 µg/g) in FA1 and FA2. Leachate solution temperature showed a positive effect on the metal's leachability. In TCLP, most of the metal's leachability was observed to be higher than that of batch leaching tests. The present study suggests that, leaching of As and Se from FA samples can moderately affect ground/surface water quality at the study locations.

Pressure leaching of chalcopyrite concentrate

NASA Astrophysics Data System (ADS)

Aleksei, Kritskii; Kirill, Karimov; Stanislav, Naboichenko

2018-05-01

The results of chalcopyrite concentrate processing using low-temperature and high-temperature sulfuric acid pressure leaching are presented. A material of the following composition was used, 21.5 Cu, 0.1 Zn, 0.05 Pb, 0.04 Ni, 26.59 S, 24.52 Fe, 16.28 SiO2 (in wt.%). The influence of technological parameters on the degree of copper and iron extraction into the leach solution was studied in the wide range of values. The following conditions were suggested as the optimal for the high-temperature pressure leaching: t = 190 °C, PO2 = 0.5 MPa, CH2SO4 = 15 g/L, L:S = 6:1. At the mentioned parameters, it is possible to extract at least 98% Cu from concentrate into the leaching solution during 100 minutes. The following conditions were suggested as optimal for the low-temperature pressure leaching: t = 105 °C, PO2 = 1.3-1.5 MPa, CH2SO4 = 90 g/L, L:S = 10:1. At the mentioned parameters, it is possible to extract up to 83% Cu from the concentrate into the leach solution during 300-360 minutes.

Succinic acid-based leaching system: A sustainable process for recovery of valuable metals from spent Li-ion batteries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Li; Qu, Wenjie; Zhang, Xiaoxiao

A hydrometallurgical method involving natural organic acid leaching has been developed for recovery of lithium and cobalt from the cathode active materials in spent lithium-ion batteries. Succinic acid is employed as leaching agent and H2O2 as reductant. The cobalt and lithium contents from the succinic acid-based treatment of spent batteries are determined by inductively coupled plasma-optical emission spectroscopy to calculate the leaching efficiency. The spent LiCoO2 samples after calcination and the residues after leaching are characterized by X-ray diffraction and scanning electron microscopy. The results show that nearly 100% of cobalt and more than 96% of lithium are leached undermore » optimal conditions: succinic acid concentration of 1.5 mol L-1, H2O2 content of 4 vol.%, solid-to-liquid ratio of 15 g L-1, temperature of 70 °C, and reaction time of 40 min. Results are also given for fitting of the experimental data to acid leaching kinetic models.« less

The ultrasonically assisted metals recovery treatment of printed circuit board waste sludge by leaching separation.

PubMed

Xie, Fengchun; Li, Haiying; Ma, Yang; Li, Chuncheng; Cai, Tingting; Huang, Zhiyuan; Yuan, Gaoqing

2009-10-15

This paper provides a practical technique that realized industrial scale copper and iron separation from printed circuit board (PCB) waste sludge by ultrasonically assisted acid leaching in a low cost, low energy consumption and zero discharge of wastes manner. The separation efficiencies of copper and iron from acid leaching with assistance of ultrasound were compared with the one without assistance of ultrasound and the effects of the leaching procedure, pH value, and ultrasonic strength have been investigated in the paper. With the appropriate leaching procedure, a final pH of 3.0, an ultrasonic generator power of 160 W (in 1l tank), leaching time of 60 min, leaching efficiencies of copper and iron had reached 97.83% and 1.23%, respectively. Therefore the separation of copper and iron in PCB waste sludge was virtually achieved. The lab results had been successfully applied to the industrial scaled applications in a heavy metal recovery plant in city of Huizhou, China for more than two years. It has great potentials to be used in even the broad metal recovery practices.

Organic compounds leached from fast pyrolysis mallee leaf and bark biochars.

PubMed

Lievens, Caroline; Mourant, Daniel; Gunawan, Richard; Hu, Xun; Wang, Yi

2015-11-01

Characterization of organic compounds leached from biochars is essential in assessing the possible toxicity of the biochar to the soils' biota. In this study the nature of the leached organic compounds from Mallee biochars, produced from pyrolysis of Mallee leaf and bark in a fluidised-bed pyrolyser at 400 and 580°C was investigated. Light bio-oil compounds and aromatic organic compounds were investigated. The 'bio-oil like' light compounds from leaf and bark biochars 'surfaces were obtained after leaching the chars with a solvent, suitable to dissolve the respective bio-oils. GC/MS was implemented to investigate the leachates. Phenolics, which are potentially harmful toxins, were detected and their concentration shown to be dependent on the char's origin and the char production temperature. Further, to simulate biochars amendment to soils, the chars were leached with water. The water-leached aromatic compounds from leaf and bark biochars were characterized using UV-fluorescence spectroscopy. Those results suggested that biochars contain leachable compounds of which the nature and amount is dependent on the biomass feedstock, pyrolysis temperature and leaching time. Copyright © 2014 Elsevier Ltd. All rights reserved.

Assessment risk of phosphorus leaching from calcareous soils using soil test phosphorus.

PubMed

Jalali, Mohsen; Jalali, Mahdi

2017-03-01

Accurate estimation of phosphorus (P) leaching is important because excess P may reduce surface and ground water quality. Little attention has been paid to estimate P leaching from soil tests in calcareous soils. The relation between different soil tests P (STP), P sorption index (PSI) and degree of P saturation (DPS) and leaching of P were examined for assessing the risk of P loss from calcareous soils. Columns leaching repacked with native soils were leached with either distilled water or 10 mM CaCl 2 solutions, separately. Four leaching events were performed at four days, and 28.7 mm of distilled water or 10 mM CaCl 2 solutions was applied at each leaching events. Compared with distilled water, CaCl 2 had a small ability to solubilize P from soils. Concentration of P in leachate in both leaching solutions was exceeding 0.1 mg l -1 associated with eutrophication. Cumulative P leached P was ranged from 0.17 to 18.59 mg P kg -1 and 0.21-8.16 mg P kg -1 , when distilled water and 10 mM CaCl 2 solutions were applied, respectively and it was higher in sandy clay loam soils compared with clay soils. Among evaluated environmental soil P tests, P CaCl2-3h (P extracted by 10 mM CaCl 2 for 3 h), P CaCl2-1h (P extracted by 10 mM CaCl 2 for 1 h) were more accurate than other soil P tests for predicting P concentration in the leachates in both leaching solutions and accounting for 83% and 72% of variation of P concentration, respectively. The water extractable P (WEP) (r = 0.771) and Olsen-P (P Ols )(r = 0.739) were significantly related to the leached P concentration using distilled water solution in a split line model, with a change point of 27.4 mg P kg -1 and 61.5 mg P kg -1 , respectively. Various DPS were calculated and related to the leached P concentration. Based on P extracted by Mehlich-3 (P M3 ) and HCl (P HCl ) and PSI, the change point of the relationship between leached P concentration and DPS M3-3 (P M3 (P M3 +PSI)×100) and DPS HCl-2 (P HCl (P HCl +PSI)×100) for both leaching solutions was approximately the same, thus a mean value of 49% for DPS M3-3 and 73% for DPS HCl-2 was obtained. Soils were grouped into four categories of increasing P leaching potential based on WEP, P Ols , and DPS M3-3 . The results indicated that 8.00%-25.50% of the soil grouped in no risk category whereas 8.00%-13.70% of the soils fell into the high risk category. Copyright © 2016 Elsevier Ltd. All rights reserved.

40 CFR 440.30 - Applicability; description of the uranium, radium and vanadium ores subcategory.

Code of Federal Regulations, 2014 CFR

2014-07-01

... vanadium ores are produced; and (b) mills using the acid leach, alkaline leach, or combined acid and alkaline leach process for the extraction of uranium, radium and vanadium. Only vanadium byproduct...

40 CFR 440.30 - Applicability; description of the uranium, radium and vanadium ores subcategory.

Code of Federal Regulations, 2012 CFR

2012-07-01

... vanadium ores are produced; and (b) mills using the acid leach, alkaline leach, or combined acid and alkaline leach process for the extraction of uranium, radium and vanadium. Only vanadium byproduct...

40 CFR 440.30 - Applicability; description of the uranium, radium and vanadium ores subcategory.

Code of Federal Regulations, 2013 CFR

2013-07-01

... vanadium ores are produced; and (b) mills using the acid leach, alkaline leach, or combined acid and alkaline leach process for the extraction of uranium, radium and vanadium. Only vanadium byproduct...

LEACHING BOUNDARY IN CEMENT-BASED WASTE FORMS

EPA Science Inventory

Cement-based fixation systems are among the most commonly employed stabilization/solidification techniques. These cement haste mixtures, however, are vulnerable to ardic leaching solutions. Leaching of cement-based waste forms in acetic acid solutions with different acidic streng...

Leaching behavior of lanthanum, nickel and iron from spent catalyst using inorganic acids

NASA Astrophysics Data System (ADS)

Astuti, W.; Prilitasari, N. M.; Iskandar, Y.; Bratakusuma, D.; Petrus, H. T. B. M.

2018-01-01

Highly technological applications of rare earth metals (REs) and scarcity of supply have become an incentive torecover the REs from various resources, which include high grade and low grade ores, as well as recycledwaste materials. Spent hydrocracking catalyst contain lanthanum and a variety of valuable metals such as nickel and iron. This study investigated the recovery of lanthanum, nickel and iron from spent hydrocracking catalyst by leaching using various inorganic acid (sulfuric acid, hydrochloric acid, and nitric acid). The effect of acid concentration, type of acid and leaching temperature was conducted to study the leaching behavior of each valuable metal from spent-catalyst. It has been shown that it is possible to recover more than 90% of lanthanum, however the leaching efficiency of nickel and iron in this process was very low. It can be concluded that the leaching process is selective for lanthanum recovery from hydrocracking spent-catalyst.

Study on the effect of innovative leaching solvent on the oil removal for oily drilling cuttings

NASA Astrophysics Data System (ADS)

Li, Long; Ma, Cha; Hao, Weiwei; Li, Mu; Huang, Zhao; Liu, Yushuang

2018-02-01

A new type of leaching solvent for oily drilling cuttings was developed, and the effect of leaching solvent on the oil removal for oily cuttings was investigated. The results indicated that the leaching solvent had good capacity of oil removal for oily cuttings, and the oil content of treated cuttings is less than 0.6%. The leaching solvent could be separated from the oil phase through distillation, and the recyclable solvent could be reused to treat other cuttings. Moreover, oil resources adsorbed on the oily cuttings could be recycled and reused to prepare new drilling fluids, so the drilling cost could be reduced greatly. As a result, the leaching solvent could treat the oily cuttings effectively, and recycle and reuse oil resources, and thus produce great economic benefits. It can play an essential role in safe drilling jobs and improvement of drilling efficiency in the future.

Long-term leaching of photovoltaic modules

NASA Astrophysics Data System (ADS)

Nover, Jessica; Zapf-Gottwick, Renate; Feifel, Carolin; Koch, Michael; Metzger, Jörg W.; Werner, Jürgen H.

2017-08-01

Some photovoltaic module technologies use toxic materials. We report long-term leaching on photovoltaic module pieces of 5 × 5 cm2 size. The pieces are cut out from modules of the four major commercial photovoltaic technologies: crystalline and amorphous silicon, cadmium telluride as well as from copper indium gallium diselenide. To simulate different environmental conditions, leaching occurs at room temperature in three different water-based solutions with pH 3, 7, and 11. No agitation is performed to simulate more representative field conditions. After 360 days, about 1.4% of lead from crystalline silicon module pieces and 62% of cadmium from cadmium telluride module pieces are leached out in acidic solutions. The leaching depends heavily on the pH and the redox potential of the aqueous solutions and it increases with time. The leaching behavior is predictable by thermodynamic stability considerations. These predictions are in good agreement with the experimental results.

Kinetic Aspects of Leaching Zinc from Waste Galvanizing Zinc by Using Hydrochloric Acid Solutions

NASA Astrophysics Data System (ADS)

Sminčáková, Emília; Trpčevská, Jarmila; Pirošková, Jana

2017-10-01

In this work, the results of acid leaching of flux skimmings coming from two plants are presented. Sample A contained two phases, Zn(OH)Cl and NH4Cl. In sample B, the presence of three phases, Zn5(OH)8Cl2·H2O, (NH4)2(ZnCl4) and ZnCl2(NH3)2, was proved. The aqueous solution of hydrochloric acid and distilled water was used as the leaching medium. The effects of the leaching time, temperature and concentration of the leaching medium on the zinc extraction were investigated. The apparent activation energy, E a = 4.61 kJ mol-1, and apparent reaction order n = 0.18 for sample A, and the values E a = 6.28 kJ mol-1 and n = 0.33 for sample B were experimentally determined. Zinc leaching in acid medium is a diffusion-controlled process.

About microcracking due to leaching in cementitious composites: X-ray microtomography description and numerical approach

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rougelot, Thomas; Burlion, Nicolas, E-mail: nicolas.burlion@polytech-lille.f; Bernard, Dominique

2010-02-15

Chemical shock of cement based materials leads to significant degradation of their physical properties. A typical scenario is a calcium leaching due to water (water with very low pH compared with that of pore fluid). The main objective of this paper is to evaluate the evolution of microstructure induced by leaching of a cementitious composite using synchrotron X-ray micro tomography, mainly from an experimental point of view. In this particular case, it was possible to identify cracking induced by leaching. After a description of the degradation mechanism and the X-ray synchrotron microtomographic analysis, numerical simulations are performed in order tomore » show that cracking is induced by an initial pre-stressing of the composite, coupled with decalcification shrinkage and dramatic decrease in tensile strength during leaching. X-ray microtomography analysis allowed to make evidence of an induced microcracking in cementitious material submitted to leaching.« less

PEP Run Report for Integrated Test A, Caustic Leaching in UFP-VSL-T01A, Oxidative Leaching in UFP-VSL-T02A

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guzman-Leong, Consuelo E.; Bredt, Ofelia P.; Burns, Carolyn A.

2009-12-04

Pacific Northwest National Laboratory (PNNL) was tasked by Bechtel National Inc. (BNI) on the River Protection Project-Hanford Tank Waste Treatment and Immobilization Plant (RPP-WTP) project to perform research and development activities to resolve technical issues identified for the Pretreatment Facility (PTF). The Pretreatment Engineering Platform (PEP) was designed and constructed and operated as part of a plan to respond to issue M12, “Undemonstrated Leaching Processes.”(a) The PEP, located in the Process Engineering Laboratory-West (PDLW) located in Richland, Washington, is a 1/4.5-scale test platform designed to simulate the WTP pretreatment caustic leaching, oxidative leaching, ultrafiltration solids concentration, and slurry washing processes.more » The PEP replicates the WTP leaching processes using prototypic equipment and control strategies. The PEP also includes non-prototypic ancillary equipment to support the core processing.« less