Embed Size (px)
Citation preview
Comprobantes:
Presentaciones en Congresos: Posters
NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing
Public concern over the toxicity of nanoparticles (NPs) is growing due to the
rapid development of nanotechnology. Inorganic NPs (metal and metal
oxides) have received increasing interest due to their extensive applications
in medicine (Au, Ag), cosmetics (TiO2, ZnO, Fe2O3) and manufacturing
(CeO2, SiO2, Al2O3). An important mechanism of nanotoxicity is oxidative
stress resulting from reactive oxygen species (ROS).
Evaluate the chemical production of ROS by inorganic NPs oxidizing the
mammalian phenolic compound, L-3,4-dihydroxyphemylalanine (L-dopa),
using a ROS sensitive dye, 2',7'-diclorodihydrofluorescein (DCFH).
• HfO2 (immersion lithography)
• SiO2, CeO2, Al2O3 (CMP)
• Others: Fe2O3, TiO2, ZrO2, etc.
Inorganic Oxide Nanoparticles Promote the Formation of
Reactive Oxygen Species (ROS)
Background
HfO2
ROS indicator-dye reaction Based on fluorescence
Antonia Luna, Angel Cobo, Reyes Sierra, Jim Field Chemical & Environmental Engineering University of Arizona
Objective
Nanomaterials
Methods
Mn2O3
ZnO
R
OH
OH R
O
OH R
O
O
CeO2 Ce3+ O2 O2-
catechol semiquinone quinone
nanoparticle
ROS
oxidativecoupling
H2O2, HO
L-dopa Semiquinone Quinone
Nanoparticles
ROS
ROS reaction Aerobic - Anaerobic
2′,7′-dichlorodihydrofluorescein
diacetate (DCFH-DA)2′,7′-dichlorodihydrofluorescein
(DCFH)
2′,7′-dichlorofluorescin
(DCF)
esteraseROS
Fluorescent
ROS
Sonicated
pH 7.2
NPs
Nonfluorescent
ROS dye
L-dopa
Incubated in phosphate
buffer pH 7.4 at 37 ºC, in the dark
Head space
flushed with N2 gas
Fluorescent
Measurements
Hypothetical mechanism for the formation of ROS (CeO2 NPs as an example)
Results
0.0
0.2
0.4
0.6
0.8
1.0
1.2
Ra
te F
orm
ati
on
DC
F (µ
M h
-1)
Nanoparticle Treatment
0.0
1.0
2.0
3.0
4.0
5.0
Rate
Fo
rmati
on
DC
F (µ
M h
-1)
Nanoparticle Treatment
Interaction of phenolic
biomolecules with NPs
increases ROS.
ROS formation
requires O2
• Most inorganic NPs studied enhanced the formation of ROS via chemical reactions with biomolecules susceptible to oxidation (such as L-dopa) in the presence of O2.
• The concentration of CeO2 and Mn2O3 NPs enhanced ROS generation during L-dopa autoxidation or direct interaction with DCFH, respectively.
• Mn2O3 oxidized DCFH in a reaction that did not require O2 or L-dopa, suggesting a direct redox reaction between the Mn2O3 and the dye.
• Nano-sized CeO2, Mn2O3 and to a lesser extent Fe0 formed hydroxyl radicals as evidenced by electron paramagnetic resonance (EPR) results.
• The chemical assay with L-dopa and DCFH developed in this study is a rapid method to screen for chemical ROS production by NPs.
Fig 1. Rate of DCFH oxidation to DCF in the presence of NPs
with and without L-dopa. “None 1-4” = Controls with only L-dopa
NPs with L-dopa
NPs alone
Fig 2. Time course of DCFH oxidation to DCF as a
function of CeO2 and Mn2O3 NPs concentration.
3400 3420 3440 3460
EP
R A
mp
litu
de
Bo (G)
Mn2O3
CeO2
Fe0
Fig 3. DCFH oxidation under aerobic and anoxic conditions.
Fig 4. EPR spectra of DMPO-OH adduct in aerobic aqueous
suspensions of CeO2 & Mn2O3 NPs at 1,000 mg L-1.
Conclusions
Time (h)
Buffer
Buffer
CeO2 with L-dopa
Mn2O3 NPs alone
DC
F (
uM
)
DC
F (
uM
)
NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing
0
5
10
15
20
0 10 20 30 40 50
DC
F (u
M)
Time (h)
Mn2O3-aerobicMn2O3-anaerobic
CeO2+ L-dopa -aerobic
L-dopa-aerobic
All others-anaerobic
1) l,4-Dioxane: A Possible Contaminant Found in the Tucson Groundwater System
Name(s): Rachel M Martinez Department(s): College of Pharmacy
The purpose of this project is to examine and spread the awareness to the Tucson community about l,4-Dioxane, a possibly carcinogenic toxin found in the city's groundwater system. During the World War II era, Tucson's economy received a generous opportunity to open up a Hughes Aircraft plant to help with the war effort. For over 30 years, Hughes was responsible for supplying the United States Armed Forces with airplanes. The manufacturing of these airplanes required the usage of many harsh metal degreasers such as Trichloroethylene (TCE) and also required the usage of 1,CDioxane (a solvent stabilizer that helps the metal degreaser work to its full potential). Since Hughes did not supply any type of hazardous waste options, these two chemicals were dumped onto open land, and gradually seeped into the groundwater system. There has been much publicity of TCE contamination on the South side part of Tucson, but not 1,4-Dioxane. Because of i t s chemical properties, the 1,4-Dioxane plume is larger and affects a larger population. This research project will show that 1,4-Dioxane is much more evasive and cannot be "filtered" out of the system like it was originally thought.
2) Removal of Nitrate and Hexavalent Uranium from Groundwater in Sequential Packet Bioreactors
Names(s): Antonia Luna-Velasco, Reyes Sierra-Alvarez, Beatriz Castro, Jim A. Field Department(s): chemical & Environmental Engineering
Uranium mining and processing has led to widespread uranium and nitrate contamination in groundwater. Bioremediation of uranium can be achieved by bacteria that reduce the soluble hexavalent form (uV1) to the insoluble tetravalent form (u'"), thereby preventing i ts migration with groundwater. However, nitrate causes the oxidation of u'", which results in uranium remobilization. In this research, sequential biotreatment of
nitrate and uV1 co-contamination is proposed. This innovate treatment system consists of a bioreactor packed with elemental sulfur used for denitrification, followed by a bioreactor packed with a mixture of zero- valent iron (WI) and sand for uranium removal. Nitrate and uranium in synthetic groundwater were successfully removed to below the maximum contaminant level of 10 mg L-' and 30 ug L: respectively. Furthermore, microbial activity in the ZVl/sand bioreactor was found to greatly enhance uranium reduction. Sulfide produced in the denitrifying bioreactor precipitated in the ZVI bioreactor as iron sulfide, which is a mineral that can help protect from re-oxidation.
3) Cleaning Up the Water Supply: Relevance of Trace Waterborne Contaminants in Wastewater
Name(s): Van Zhu, Mario R. Rojas, A. Eduardo Shez, Robert Arnold, Leah Edwards, Ben Long Department(s): Chemical & Environmental Engineering
here is increasing concern on the presence of persistent contaminants of anthropogenic origin that are discharge intp natural water systems from wastewater treatment plants (WWTPs). These compounds are not destroyed by conventional water treatment technologies and, even though they are present in WWTP effluent at trace concentrations, direct ecosystem effects have been widely documented. The objective of this work is to assess the effectiveness of current wastewater treatment technologies in the removal or destruction of emerging organic contaminants of concern. Contaminants of interest include pharmaceuticals, pesticides, endocrine disrupting compounds, personal care products, flame retardants, surfactants, and other chemicals whose fate in the environment is not completely understood. The literature has been surveyed extensively for laboratory, pilot and full-scale studies on the effectiveness of different treatment processes (biological, chemical and physical) to destroy or remove trace organic contaminants from wastewater, including our own work on endocrine disrupters and flame retardants. We establish patterns based on the extensive data available that will help identify optimum treatment strategies for removal of the selected contaminants.
chlorate and oxygen. Complete AS"' oxidation was observed in the cultures amended with nitrate and oxygen. Partial oxidation of AS''' occurred with nitrite by strains EC3 and MC. In all the cultures, nitrate was reduced to nitrite. Several electron donors were used to study their suitability for nitrate reduction by the strains. Hydrogen and acetate were readily utilized by all the cultures. The multiple metabolic abilities of these three AS"'-oxidizing bacteria provide a better understanding of the biotransformation pathways within the arsenic cycle in the environment.
8 ) Use of ZVI for the bioremediation of U(VI) contaminated groundwater
Name(s): Aida Tapia-Rodriguez, Antonia Luna-Velasco, Angela L. Athey, Wenjie Sun, Jim A. Field, Reyes Sierra-Alvarez Department(s): Chemical & Environmental Engineering
A history of unregulated waste disposal and releases during uranium mining and processing allowed the contamination of important ground aquifers. Evidence of chemical risks associated to the soluble forms of uranium has highlighted the need for remediation. Past studies have recognized important features of m i f o r removing U(VI) from water through chemical reduction as insoluble U(IV); this mechanism, though, does not ensure high stability due to its slow kinetics. The objective of this research is to demonstrate that a microbial co-culture can enhance U(VI) reduction using ZVI as electron donor. An additional objective is to evaluate the possible mechanisms by which this process occurs. Enrichment cultures were developed with ZVI, and a major contribution of biological activity to the reduction of U(VI) was observed in comparison to abiotic controls. Also, experiments revealed that Hz production by abiotic corrosion of ZVI was greater than in biological treatments, probably due to consumption of accumulated H2 by members of the co- culture.
9) Removal of Endocrine Disrupting Compounds from Water Resources using Agarose Immobilized Horseradish Peroxidase Enzyme
Name(+ Debashree Basudhar, Omar Gonzelez, Roberto Guzman Department(s): Chemistry, Chemical & Environmental Engineering
Endocrine disrupting chemicals (EDC) have the ability to disrupt the endocrine system of human and wildlifeleven at nanomolar concentration either by mimicking the natural hormone or by blocking it. This may not only result in developmental and reproductive problems but may also lead to cancer. Some of the sources of EDC in water systems are natural hormones, various pharmaceuticals such as birth control pills, hormone replacement therapy products and other steroids. These products are used by humans, which is in turn excreted and released into wastewater systems. Pesticides and various industrial wastes are also some common sources of EDCs that often end up in water bodies. In spite of low solubility of nanogram per liter, they pose an incredible health hazard due to low chemical and biodegradability and nanomolar biological activity.
We have explored the feasibility of enzymatic removal of various endocrine disrupting compounds immobilized on solid support. In this direction, the effect of pH and temperature on activity of immobilized Horse radish peroxidase (HRP) was compared to free HRP followed by effectiveness of removal of EDC and reusability of immobilized HRP was investigated.
10) Fate of Metal Oxide Nanoparticles in Municipal Wastewater Treatment
Name(s): Jeff Rottman, Isabel Barbero, Monica Rodriguez, Farhang Shadman, Reyes Sierra Department(s): Chemical & Environmental Engineering
Nanomaterials exhibit unique properties which have provided for increased use in various manufacturing processes. Little specific
nna Mikoia, Helsinki Universityof Technology, Tietotie irene Slavik, TU Dresden, GERMANY (irene.slavik@tu-
IE, Helsinki, FINLAND ([email protected]) dresden.de)
P45: Innovative Approach to Centrate P48: Interactions Between Inorganic Oxide Nitrification Accomplishes Multiple Goals - Nanoparticles and Municipal Wastewater Nitrogen Removal and Odor Control Const i tuents: Implications for Nanoparticle
Removal during Biological Wastewater Treatment R. Sierra-Alvarez, I. Barbero, J.Rottman, IM.Rodriguez,
In 2001, the City of Phoenix committed to the conversion A. Luna-Velasco, F. Shadman, I. A. Field of the existing 27 million gallon high-rate anaerobic digestion process at the 9lstt\venue Wastewater Engineered nanomateriais (ENM) are manmade Treatment Plant (WWIP) to a multi-phase process (acid1 structures with diameters of less than 100 nm, that are methane, mesophiiicithermophilic) to optimize the finding increasing application in a variety of industrial digestion facility capacity and achieve Class A biosolids. processes and consumer products. Recent reports The improved solids reduction associated with the muiti- confirming the toxicity of some ENMs indicate the need phase process is anticipated to double the ammonia to advance our understanding of the fate and sources load in the dewatered sludge centrate stream, which is of NPs in the environment. Municipal treatment works currentiy treated in the NdeN (nitrification/denitrification) could be important point sources of ENM. The aim of activated sfudge facilities. in order to meet the this study is to investigate the impact of real municipal efliuent total nitrogen discharge iimits of 10 mg/L as N wastewater and specific wastewater characteristics on the with the increased ammonia loading, a separate centrate aggregation behavior of commonly used inorganic oxide nitrification system was incorporated into the plant's nanomaterials (i.e, SiO,, CeO,, and Ai203). Our results process flow scheme where ammonia is oxidized to nitrite1 indicate that dilution with municipal wastewater can nitrate in a dedicated aerobic reactor and the NOx-N have a profound effect on the fate and mobility of NPs. rich stream is discharged to the planrs headworks for When diluted with municipal wastewater, the stability of subsequent denitrification. This paper wiii describe how nano-sized CeO, and AI,O, dispersions decreased at ail centrate nitrification is being implemented and present the pH values tested &lo), and the average particle size results of the odor control savings being realized with the (APS) of these materials increased to the micron-size nitrified centrate dosing to the headworks. range. In contrast, the APS of SiO, NP was not affected
by dilution with wastewater. Several organic compounds, J. Coughenour II, City of Phoenix, Arizona 91st Avenue including proteins, amino acids and carboxyiic acids Multi-Cities WWTP, 5615 South 91st Avenue, Tolieson, commoniy found in municipal wastewater, were found to USA ([email protected]) altei the tendency of inorganic oxide NPs to aggregate.
Future work will expand research on the impact of P47: Integrative Modeling of Reservoir wastewater chemistry on the stability of NP dispersions. Management for Drinking Water Production This knowledge is needed to understand the fate of ENM I. Slavik, B. Skibinski, S. Watzlawik during municipal wastewater treatment, and i t could be
applied to develop novel technologies for the removal of Raw water reservoirs for drinking water production NPs prior to discharge intosurface water. predominantly have to guarantee raw water in sufficient quantity. Furthermore, as water quality considerably Reyes sierra-Aivarer, University of Arizona , Tucson, USA impacts the efforts to be taken in drinking water ([email protected]) production, demands on water quality are high. Management of dammed reservoirs can considerably P49: ~inetics of Ciprofloxacin Degradation impact water quaiity. Finally, many reservoirs have by ~dvanced Oxidation Processes: Effects to fulfiil demands for fiood risk management, a good o f Natural Organic Matter Matrices ecological state of the water body and the reaches of C. Marron, L. Blaney, D. Lawler, L. Katz rivers downstream, energy production and recreational use. Managing such multipurpose reservoirs is resulting The implications ofindirect and direct water reuse are in numerous conflicts of interest. Combining different of great importance as the pathway from wastewater mechanistic models, a decision support tool for reservoir ' to drinking water becomes increasingiy shorter. management was developed to help solve these conflicts Furthermore, the presence of pharmacologicaiiy active and to find an ideal management strategy.
state and parameter estimation method, which measures sludge plant fed with a nano-sized Ce02 dispersion and and controls the MBR system using a model based real municipal wastewater indicated that a significant. approach and limited measurements. With this approach, fraction of the CeO2 NPs was removed by formation of limitations of the feedback strategy can be overcome by large aggregates or bacteria-bound aggregates. However, predicting the impact of time varying disturbances on the unagglomerated cerium oxide was also detected in the
treated water. We are not aware of previous reports considering the fate of CeO, in actual, non-synthetic,
Vijaysai Prasad, GE Water and Process Technologies, municipal wastewater. Additional experiments confirmed No 122, GE ITC Pvi Ltd., Export Promotion Industrial that organic constituents in the wastewater, such as Park, Whitefield Road, Hoodi Viilage, Bangalore, INDIA proteins, amino acids, and synthetic dispersants, affect ([email protected]) the stability of these NPs in aqueous solution. Future
research will investigate the fate of alumina during P68: Remediation of Acid Mine Drainage wastewater treatment. These studies can provide valuable in Sulfate-Reducing Permeable Reactive information to understand the significance of municipal Barriers Packed with Zero-Valent Iron wastewater treatment plants as point sources of NPS and A. Luna-Velasco, R. Sierra-Alvarez, 8. Howard, 1. A. Field
This study investigated zero-valent iron (ZVi) as novel, slow-release electron-donating material to support the in situ treatment of acid drainage by sulfate reducing bacteria in permeable reactive biobarriers. Our results demonstrated that N I is readily utilized as an electron source by sulfate reducing microorganisms. Furthermore, the suppiementation of ZVi provided several benefits over organic substrates, including sequestration of excess sulfide as insoluble iron suifides, generation of high ievels
devise new approaches for their removal
Reyes Sierra-Aivarez, University of Arizona , Tucson, USA ([email protected])
P70: Removal of Heavy Metals using Commercial Metal Oxide Nanoparticles H. Shipley, K. Engates, 1. Hu
Levels of heavy metals found in rocks and soils are usualiy not cause for concern. By contrast,
of alkaltntiy due to anoxlc corrosion, and enhanced heavy anthropogenic actlv~ttes includ~ng, but not itm~ted - 1 metal removal.
keyes Sierra-Alvarez, University of Arizona ,Tucson, USA ([email protected])
P69: Removal of Ce02 and A1203 Nanoparticles in Semiconductor Manufacturing Effluents during Activated Sludge Treatment F. Gomez, I. Barbero, M. Rodriguez, A. Luna-Velasco, F. Shadman, 1. A. Field, R. Sierra-Alvarez
Nano-sized ceria (CeO,), and alumina (A1203) are used in many industrial processes, including semiconductor manufacturing. Slurries utilized in chemicai mechanical planarization (CMP) contain abrasive nanoparticies (NPs) of these inorganic oxides to facilitate the polishing of wafers. These inorganic oxides also have rapidiy growing applications in catalysis, polymers, coatings, etc. In spite of the concern about the environmentai, safety and heaith aspects of these and other nanomaterials, information about their fate during municipal wastewater treatment isvery limited. The objective of this research is to investigate the removal of CMP nanoparticies during municipal wastewater treatment and elucidate the main mechanisms contributing to their (partial) removal. Experiments conducted in a laboratory-scale activated
to, industrial, agriculturai, and military sources have contributed to heavy metai pollution(Tabacki et al. 2004), which pose human heaith risks (USEPA 2006). in addition, 20 to 50 miilion tons of electronic waste -or 'e-waste'- generated annually from cell phones, computers and other disposable electronics contain potentialiy harmful levels of heavy metals that may leach into the environment and make their way to drinking water sources (USEPA2006). In this work it is shown that commercial metal oxide nanoparticles (hematite and titanium dioxide) can be used to remove heavy metals (Pb, Cd, Zn, Cu, and Ni) from water. irreversible sorption of Pb was observed to the metai oxide nanoparticles and exhaustion studies showed after 4 cycles that the particles could stili be used to remove metals.
Heather Shipley, Universityof Texas-San Antonio, One UTSA Circle, San Antonio, USA (heather.shipley@utsa. edu)
P71: Removal of Oxidized Contaminants from High TDS Solutions Using the H2- based Membrane Biofilm Reactor (MBfR) S. W. van Ginkel, 9. E. Rlttmann
The HZ-based membrane biofiirn reactor (MBfR) was shown to simultaneously reduce nitrate and selenate in
NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing
The fast growth of nanotechnology and the increasing use of engineered
nanomaterials has led to a growing public concern about potential toxic effects
of nanomaterials. Toxicity research is a high priority for the semiconductor
industry since this sector is exploiting the use of various nanomaterials in its
manufacturing process.
• Characterize the potential toxicity of current and emerging
nanoparticles (NPs) & NPs byproducts.
• Develop new rapid methodologies for assessing and predicting toxicity.
HfO2 (immersion lithography)
SiO2, CeO2, Al2O3 (CMP)
Others: Fe2O3, TiO2, ZrO2, etc.
Environmental Safety and Health (ESH) Impacts of Emerging
Nanoparticles and Byproducts from Semiconductor Manufacturing
Results
Live/Dead
50% death
Microtox
50 % inhib.
mg/L
Methanogenic
50 % inhib.
HfO2 >2,000 3,000 >2,500
CeO2 2,500* >1,000* >1,000
Background
Objectives
Materials
* with dispersant
Table 1. Toxicity of nano-sized HfO2 (100 nm) and CeO2 (20 nm).
The proposed reaction mechanism for the formation of ROS in the cell-free assay is
show below:
Nanoparticles
Biological targets
Human skin cell line (Hacat)
Bacterium (Vibrio fischeri), Microtox test
Others (methanogens, bacteria, yeast etc)
Fig. 1. Live/Dead response with HfO2 NPs.
250 mg/L 1,000 mg/L 2,500 mg/L
Live/Dead assay
HaCat skin cell line
Mitochondrial Toxicity
Test or MTT
(ureter cells)
Microtox
(Vibrio fisheri)
3-(4,5-Dimethylthiazol-2-yl)-2,5-
diphenyltetrazolium bromide Purple formazan
Main toxicity tests utilized
Methods
Live: GreenCalcein AM
Dead: RedEthidium Homodimer 1
Fig. 2. Production of ROS vs. Microtox inhibition.
0
30
60
90
120
300 300 500 500 500 1000 500
Dispersed nanoparticles (mg/L)
% i
nh
ibit
ion
Series20
2
4
6
HfO2 CeO2 Mn2O3 Fe2O3 Feº ZrO2 Al2O3
DC
F
uM
/h
Nanoparticles alone Nanoparticles + L dopa
Microtox
ROS
Results of the Live/Dead assay indicate that HfO2 (100 nm) only displays slight
citotoxicity (Fig. 1).
The most reactive NPs in the ROS cell-free assay displayed the highest toxicity.
Conclusions
Reactive oxygen species (ROS) production in cell-free system
2′,7′-dichlorodihydrofluorescein
diacetate (DCFH-DA)2′,7′-dichlorodihydrofluorescein
(DCFH)2′,7′-dichlorofluorescin
(DCF)
esterase ROS
Fluorescent
Development of new techniques
XCELLigence
Wound healing
Oxygen uptake
Impedance measurement
Rel
ativ
e im
ped
ance
Cell adhesion-based assay: Time to close scrape wound
0.0000
0.0003
0.0006
0.0009
0.0012
0 4 8 12 16 20 24
Time (hrs)
Oxyg
en
(m
ols
)
0 ppm
500 ppm
1000 ppmFluorescent dye-free assay with
eukaryotic cells (yeast)
• CeO2, HfO2, Al2O3, ZrO2 NPs showed mild to no toxicity.
• ROS production in the cell-free assay correlated with NP toxicity.
• New high-throughput toxicity assays are under development for NP testing.
Antonia Luna1, Angel Cobo1, Citlali Garcia1, Lila Otero1, Cara Sherwood2, Scott Boitano2, Reyes Sierra1, Farhang Shadman1, Buddy Ratner3, Jim Field1
Chemical & Environmental Eng.1, Arizona Respiratory Center2, University of Arizona, and Univ. of Washington Engineered Biomaterials Center
2009 Annual AIChE Meeting Nashville TN, USA.
November 8-13.
Toxicity of Nanoparticles: Cerium and Hafnium Oxides
Monday, November 9, 2009
Ryman Hall B1/B2 (Gaylord Opryland Hotel)
Dominique A. Ingato, Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, PA
James A. Field, Chemical and Environmental Engineering, University of Arizona, Tucson, AZ
Reyes Sierra, Chemical and Environmental Engineering, University of Arizona, Tucson, AZ
Antonia Luna-Velasco, Chemical and Environmental Engineering, University of Arizona, Tucson, AZ
Nanoparticles (NPs) are defined as particles that range in size from 1 to 100 nm. NPs
play an important role in the Chemical-Mechanical Polishing (CMP) processes used by
the semiconductor industry. CMP slurries are currently being treated at waste-water
treatment (WWT) plants although the effects of NPs on WWT sludges and the
environment have not been sufficiently studied. NPs could potentially affect the
environment by changing toxin/nutrient levels, ecosystems and microstructures. The
main goal of this project was to determine the toxicity of cerium oxide NPs on
acetoclastic methanogens and aerobic bacteria found in sludges from wastewater
treatment plants. This study also includes further CeO2 toxicity tests on aquatic bacteria.
Liga: http://aiche.confex.com/aiche/2009/webprogram/Paper172871.html
3
will be based on reverse osmosis (RO) treatment of a portion of Tucson’s CAP entitlement. Unfortunately, water recovery may be limited to 75-80% to avoid membrane scaling. Should a third of Tucson’s CAP allotment receive RO treatment, the value of water lost would be about $15M per year. Clearly, there is incentive to reduce brine loss via pre-RO water softening or post-RO application of water recovery technologies. Vibratory shear-enhanced processing (VSEP) reduced overall water loss during RO/VSEP treatment to just 4%. Efforts to optimize VSEP operations are in progress. 5. Constructed Wetlands to Remove Endocrine Disruptors Name(s): Alandra Kahl, Robert Arnold, Wendell Ela, Eduardo Saez, David Quanrud Department(s): Chemical and Environmental Engineering, University of Arizona Abstract: Endocrine disrupting compounds (EDCs) are among the most important trace contaminants in wastewater. They are biologically active at vanishingly low (ng/L) concentrations, and, not surprisingly, municipal wastewater treatment plants were not designed for their removal or destruction. Consequently, they are frequently present at environmentally meaningful concentrations in treated wastewater or in s ludges derived from wastewater treatment. As municipal water budgets are strained by population growth and other competing water needs, regional water authorities increasingly rely on water reuse strategies. As such, it is particularly important to identify and treat trace contaminants with human health effects. Among the inexpensive methods for polishing wastewater effluent is wetlands treatment. In particular, this research has dealt with the fate of estrogens and other EDCs in wetland treatment processes. 6. Anaerobic Bioremediation of Hexavalent Uranium Plumes in Groundwater Name(s): Alandra Aida Tapia-Rodriguez, Antonia Luna, James A. Field, Reyes Sierra-Alvarez Department(s): Chemical and Environmental Engineering, University of Arizona Abstract: Contamination of hexavalent uranium (U(VI)), the most common form of natural uranium, has increased in the past few decades due to wastes originating from uranium extraction, processing and disposal. This soluble form of uranium presents a considerable chemotoxicity in long-term exposures, leading to damage of kidneys. The objective of this project is to
4
demonstrate that U(VI) can be biotransformed by anaerobic microbial reductive precipitation to insoluble U(IV). From batch experiments performed with different sludge inocula, results indicated that the presence of H2 readily contributes to the biological reduction of U(VI), but that endogenous substrates in the sludge can also support reduction in absence of added electron donor. A continuous experiment has also been set up with three reactors run in parallel. The reactors are packed with sludge and supplied with and without ethanol. Results confirm that the reactors provide enough U(VI) reduction, with removal efficiencies up to 99.94%. The ethanol addition was not required to achieve this efficiency. 7. Biomineralization: Implications on the Fate of Arsenic in Landfills Name(s): Fernando Alday, Christopher Olivares, A. Eduardo Sáez, Wendell Ela Department(s): Chemical and Environmental Engineering, University of Arizona Abstract: The new arsenic Maximum Contaminant Level (MCL) is causing a significant increase in the volume of arsenic-bearing solid residuals (ABSR) generated by drinking water utilities. Because of their high adsorption capacity and low cost, iron sorbents are widely utilized for treatment and comprise the bulk of the waste generated. Based on Toxicity Characteristic Leaching Procedure (TCLP) results, these ABSR may be disposed in municipal solid waste landfills. However, a mature landfill is a biotic, reducing environment where iron and arsenic may be reduced and, as a consequence, arsenic may be released to the leachate. The primary route of iron reduction in landfills is microbially mediated and biomineralization is a common by-product. In the ongoing study, biomineralization is evaluated as a key component in the processes controlling iron and arsenic leaching from ABSR in landfills. 8. Fingerprinting Water – A Seasonal Understanding of Mountain Block Chemical Weathering Processes Name(s): Angela Jardine, Peter Troch, Jon Chorover, Craig Rasmussen, Travis Huxman, Jennifer McIntosh Department(s): Hydrology and Water Resources; Soil, Water and Environmental Science; Biosphere 2, University of Arizona Abstract: In water-limited semi-arid environments, an understanding of how water interacts with the vegetation, soil, and bedrock components of the Earth’s critical zone (CZ) is essential for making sustainable water
U.S. - Mexico Binational Center
for Envlranmentai Sclences and Toxlcolo~y
characterized by infrared spectroscopy and for scanning electronic microscopy and its DDT adsorption properties were determined. The adsorption process is described by Freundlich isotherm.
The isolation of organochlorine pesticide degrading bacteria from coffee beans was done and they were identified as: Morganella morganii, Pseudomona aeruginosa, P. putida, F.'oryzihabitans y Stenotrophomonas nialtophilia. Effect of carbon source on bacterial growth and pesticide biodegradation was performed for P. aeruginosa and F. oryzihabitans in liquid media amended with glucose, peptone and ground coffee beans using 50 ppm DDT and 50 ppm endosulfan.
The highest pesticide biodegradation was obtained when the coffee bean was added as substrate. The identification by mass spectrometry of certain metabolites such as DDMU and DDOH suggests the formation of anaerobic microniches in the porous structure of coffee bean. It i s concluded that this agricultural waste is effective to eliminate organochlorine pesticides such as DDT and endosulfan by adsorption and biodegradation processes.
50. Screening of lnocula for the Microbial Reduction of Bromate using Elemental Sulfur as an Electron Donor Antonia Luna, Monserrat Chairez, Reyes Sierra, Jim A. Field The University ofArizona
Bromate (BrOJ is an inorganic compound that can cause mutagenic and carcinogenic effects at very low concentrations. Drinking water contamination by bromate is commonly associated with by-product formation during disinfection of bromide-containing drinking water with ozone or hypochlorite. In the United States of America, bromate concentrations in drinking water are already regulated [Max. Contaminant Level (MCL) = I 0 pg BrO; L-'I. Bromate is highly soluble, stable in water, and difficult to remove using conventional treatment technologies. Biological processes exploiting the ability of some microorganisms to reduce bromate to bromide (Br), a benign product, offer interesting perspectives for the bioremediation of bromate contamination.
In this study anaerobic n~icrocosms were utilized to evaluate inocula obtained from different sources [returned activated aerobic sludge (RAS), digested sewage sludge (anaerobic) and a perchlorate-reducing enrichment culture (PRB)] for their ability to reduce bromate using elemental sulfur (So) as an electron donor. The microcosms [I00 mL of culture fluid in 160 mL serum flasks flushed with N,/CO, (80120, vlv)] were incubated anaerobically in the dark at 30°C in basal mineral medium (pH 7.2). Bromate, bromide and sulfate were monitored by ion chromatography. The enriched PRB culture was the only inoculum able to reduce bromate (0.3 mM) using So as electron donor. Bromate was stoichiometrically converted to bromide (Bi) and no accumulation of intermediates occurred. The results suggest this culture could potentially be used in a biological process for the remediation of bromate.
U.S. -Mexico Binational Center
for Ltivironnleiilal Sciences and Toxicoto~
46. Process for the Bioremediation of Groundwater Contaminated with Nitrate Monserrat Chairez Llamas', Onofre Monje Amaya',', Antonia Luna', Reyes Sierra-Alvarez', Jim A. Field' 'The University of Arizona, 'University of Sonora
Nitrate in the groundwater of Arizona is a concern because concentrations are exceeding the maximum drinking water contaminant level (MCL) of 10 mg nitrate-N L-I at many locations.
This project is aimed at developing a simple low-cost, low-maintenance method to treat nitrate in contaminated groundwater. The proposed treatment system relies on the microbial reduction of nitrate to benign N2 gas by autotrophic bacteria that utilize elemental sulfur (SO) as an electron donating substrate. SO has proven to be a safe and inexpensive electron donor and requires no continuous addition. Utilization of SO precludes the presence of organic residuals in the treated water, which is one of the main disadvantages of alternative heterotrophic denitrification processes.
A continuous bioreactor (1.4 L) packed with granular SO and limestone grit, and inoculated with a chemolithotrophic denitrifying enrichment culture was fed with a synthetic groundwater amended with 14 mg nitrate-N/L. The volumetric nitrate loading was increased incrementally by decreasing the hydraulic retention time from 20.0 to 3.5 h Results indicate that this system can successfully treat nitrate with a high efficiency (99.7 t O .6%) at volumetric loads of 107 mgl(Lreactor.d) and hydraulic retention times of only 3.5 h. Nitrate was stoichiometrically converted to N2 and nitrite concentrations in the effluent were under the detection level (0.01 mg/L). These results confirm the potentials of SO-based autotrophic denitrification processes for the removal of nitrate from groundwater.
47. Immiscible Liquid Dissolution in Heterogeneous Porous Media Ann Russo, Mark L. Brusseau The University of Arizona
lmmiscible liquids have proven to be a lasting source of subsurface contamination at many hazardous waste sites. Understanding the fate and transport behavior of these contaminants will allow for better site characterization and determination of applicable remediation technologies. Experiments were conducted to investigate liquid dissolution behavior in various porous media. lmmiscible liquid dissolution was investigated at the column scale by conducting experiments using homogeneously packed columns (7cm long) containing a residual saturation of immiscible liquid, specifically trichloroethylene (TCE). The porous media used comprised different particle size distributions. Aqueous experiments were also conducted to determine the impact of sorptionldesorption on elution tailing. Dissolution experiments were then modeled with a multi- domain model. Different dissolution behaviors were observed for various porous media. Secondary steady state regions were observed in dissolution experiments with Hayhook soil as the
