Search

Mined areas near the city of Galena, Kansas, provide a source of heavy metal contamination, particularly cadmium (Cd), lead (Pb), and zinc (Zn). The metals move off-site in response to erosion by w...

Referee: Dr. Paul E. Olson, Colorado State University, Department of Biology, E414 Anatomy/Zoology Building, Fort Collins, CO 80523-1878 Plants have many beneficial effects on contaminated soils, including direct metabolism of some organic compounds, stimulation of microbial activity in the root zone, extraction of water, reduction of infiltration, improved aeration of the soil and stabilization against wind and water erosion. Some of these benefits have been explored and exploited in the newly named field of phytoremediation, whereas others remain largely in the domain of agronomy and ecology. This review attempts an assessment of the major environmental impacts of plants in general, recently termed phytotechnology, while including some case studies where particular species have been shown to have impacts on certain contaminants, more specifically termed phytoremediation. There is growing evidence that plants can have significant benefits in phytoremediating a range of complex organic molecules, includin...

Poplar trees represent one vegetation option for phytostabilization of heavy metal-contaminated sites. The objective of this study was to investigate the suitability of deep-planted hybrid poplars for phytostabilization of a heavy metal-contaminated site. Tree survival was greatly improved when trees were planted using cattle manure as a soil amendment as compared to no amendment. Survival after 3 years with manure ranged from 18 to 56% for four poplar hybrids, while without manure, the range was 0–18%. Increases in trunk diameter and tree height were also greater with manure than without after the first growing season. Zinc, Cd, Pb concentrations were as high as 3,606, 44, and 33 mg kg\U-1\N, respectively, in leaves, and there was little influence of manure amendment or hybrid. Zinc phytotoxicity may have been a factor in tree survival. Average metal concentrations in plant tissues followed the order: leaves>bark>twigs>wood for Zn and Cd, and bar>wood>twigs≅leaves for Pb. Manured treatments supported higher rates of both photosynthesis and transpiration. Comparisons among varieties indicated that DO1 and Imperial Carolina hybrids had more than twice the rates of photosynthesis of the other two hybrids and that each variety was unique in terms of water-sue efficiency (WUE), with Imperial Carolina being higher than any other hybrid. This combination of high rates of photosynthesis and high WUE suggests a unique suitability of this hybrid for remediation of this site. More extensive characterization of the hybrids under a variety of conditions, including drought, is likely to reveal more about inherent suitability of each hybrid for site-specific remediation.

Growing concerns about global warming, air pollution, and fossil fuel shortages have prompted the research and development of energy efficient electric vehicles (EVs). The United States government has a goal of putting 1 million EVs on the road by 2015. The anticipated increase in EV usage, along with the use of renewable energy sources for EV charging presents opportunities as well as technical hurdles. In this work, we propose coordinated EV charging strategies for commercial charging stations in parking lots. The focus of the research is on minimizing energy drawn from the grid while utilizing maximum energy from renewable energy resources in order to maximize benefits to parking lot owners. We propose an optimal control theory based strategy for EV charging. Specifically we derive a centralized iterative control approach in which the charging rates of EVs are optimized one at a time. Through analysis and simulations, we demonstrate that optimizing the charging rate of one vehicle at a time and repeating this process for all vehicles iteratively converges to the global optimum.

The effect of water application (e.g., through rainfall or sprinkler system) on emissions of greenhouse gases (GHGs), such as nitrous oxide (N2O), methane (CH4), and carbon dioxide (CO2), from pen surfaces of open-lot beef cattle feedlots was evaluated under controlled laboratory conditions. Soil/manure samples were collected from several randomly selected pens from two beef cattle feedlots in Kansas and were used as simulated pen surfaces. Three treatments (i.e., dry and loose, moist and loose, and moist and compacted pen surface conditions) were considered, simulating surface conditions in the field after a typical rainfall event or water application with a sprinkler system. Soil/manure and water were mixed within glass containers and analyzed for GHG emission using a photo-acoustic infrared multi-gas analyzer; emission rates were calculated from measured concentrations. GHG emissions from the dry soil/manure samples were low, with mean values of 0.02, 0.00, and 45 mg m−2 h−1 for N2O, CH4, and CO2, respectively, compared to moist soil/manure samples. Water application on the dry manure samples resulted in large peaks of GHG fluxes, with peak values of 99.2, 28.6, and 15,443 mg m−2 h−1 for N2O, CH4, and CO2, respectively. The effect of water application (e.g., through rainfall or sprinkler system) on emissions of greenhouse gases (GHGs), such as nitrous oxide (N2O), methane (CH4), and carbon dioxide (CO2), from pen surfaces of open-lot beef cattle feedlots was evaluated under controlled laboratory conditions. Soil/manure samples were collected from several randomly selected pens from two beef cattle feedlots in Kansas and were used as simulated pen surfaces. Three treatments (i.e., dry and loose, moist and loose, and moist and compacted pen surface conditions) were considered, simulating surface conditions in the field after a typical rainfall event or water application with a sprinkler system. Soil/manure and water were mixed within glass containers and analyzed for GHG emission using a photo-acoustic infrared multi-gas analyzer; emission rates were calculated from measured concentrations. GHG emissions from the dry soil/manure samples were low, with mean values of 0.02, 0.00, and 45 mg m−2 h−1 for N2O, CH4, and CO2, respectively, compared to moist soil/manure samples. Water application on the dry manure samples resulted in large peaks of GHG fluxes, with peak values of 99.2, 28.6, and 15,443 mg m−2 h−1 for N2O, CH4, and CO2, respectively.

Emission of greenhouse gases, including nitrous oxide (N2O), from open beef cattle feedlots is becoming an environmental concern; however, research measuring emission rates of N2O from open beef cattle feedlots has been limited. This study was conducted to quantify N2O emission fluxes as affected by pen surface conditions, in a commercial beef cattle feedlot in the state of Kansas, USA, from July 2010 through September 2011. The measurement period represented typical feedlot conditions, with air temperatures ranging from -24 to 39°C. Static flux chambers were used to collect gas samples from pen surfaces at 0, 15, and 30 minutes. Gas samples were analyzed with a gas chromatograph and from the measured concentrations, fluxes were calculated. Median emission flux from the moist/muddy surface condition was 2.03 mg m−2 hour−1, which was about 20 times larger than the N2O fluxes from the other pen surface conditions. In addition, N2O peaks from the moist/muddy pen surface condition were six times larger than emission peaks previously reported for agricultural soils. Emission of greenhouse gases, including nitrous oxide (N2O), from open beef cattle feedlots is becoming an environmental concern; however, research measuring emission rates of N2O from open beef cattle feedlots has been limited. This study was conducted to quantify N2O emission fluxes as affected by pen surface conditions, in a commercial beef cattle feedlot in the state of Kansas, USA, from July 2010 through September 2011. The measurement period represented typical feedlot conditions, with air temperatures ranging from -24 to 39°C. Static flux chambers were used to collect gas samples from pen surfaces at 0, 15, and 30 minutes. Gas samples were analyzed with a gas chromatograph and from the measured concentrations, fluxes were calculated. Median emission flux from the moist/muddy surface condition was 2.03 mg m−2 hour−1, which was about 20 times larger than the N2O fluxes from the other pen surface conditions. In addition, N2O peaks from the moist/muddy pen surface condition were six times larger than emission peaks previously reported for agricultural soils.

Stabilization and remediation of lead-contaminated soils has received considerable attention recently. Amending Pb-contaminated soils with phosphate as an in situ remediation option has been proposed as an alternative to other remediation options, such as soil removal. Research shows that hydroxyapatite (HA) [Ca(5)(PO(4))(3)OH] can reduce the bioavailability of Pb efficiently and thus is considered as an ideal phosphate source for formation of lead pyromorphite. Environmental models are increasingly being relied upon to help identify the limiting factors in such kind of in situ remediation. In this work, the contaminated aggregates remediation model has been developed and simulated to describe the effects of initial contaminant concentration, diffusion coefficient, and aggregate diameter on the time of remediation which is defined as the time required to reduce the aqueous phase lead concentration to

To ensure passenger safety during flight operations, the Federal Aviation Administration demands the use of glycol-based aircraft deicing fluids (ADFs) at airports. However, from the deicing process a significant amount of ADF runoff enters storm-water collection systems and/or finds its way to soil and ground-water ecosystems. The environmental impact of the ADF mixture is a combination of the extremely high biological oxygen demand from glycols and the toxicity to bacteria, aquatic organisms, and plants of the corrosion inhibitor tolyltriazole. The present paper discusses some alternatives that have been proposed to manage ADF waste and the need for an environmental management technology able to deal with both kinds of contaminants. Phytoremediation has been explored because a rhizosphere effect improves the efficiency of land treatment for many substances and only fungi and vegetation have been reported to be able to degrade the corrosion inhibitor (Wu et al. 1998). Below a toxic threshold of about 100 mg of methyl benzotriazole/L in the aqueous phase, plants can degrade approximately about 2 mg of methyl benzotriazole/(g dry root·day). Some of the advantages, difficulties, and conditions to apply the technology are outlined.

Methyl tert-butyl ether (MTBE) is an important ground-water contaminant. Gasoline spills and leaks from pipelines, underground and aboveground storage tanks, and other transport modes are major sources of MTBE contamination. A six-channel system was set up and used to examine the effect of alfalfa plants on the fate and transport of MTBE. Contamination by MTBE was established by continuously feeding a solution of 0.84 mM MTBE into each channel at 1 L/day. The concentrations of MTBE in the channel ground-water effluent, at the channel soil surface, and within alfalfa plant stems were monitored. By incorporating plant water use with the concentrations of MTBE in plant water, the authors obtained the mass fluxes of MTBE transported by alfalfa plants grown in soil channels. Even with the same contaminant concentration in the growth channel, alfalfa plants took up MTBE nonuniformly. The more vigorous the growth of plants, the higher the MTBE concentration in the plant water, and the more MTBE removed by the pl...

Concentrations measured in alfalfa plant stem segments indicated that plants grown in methyl tert-butyl ether (MTBE)-contaminated soil took up the chemical through their roots. Assuming a cylindrical shape for the plant stem, a mathematical model was developed to describe the transport of MTBE through the stems. Simulation results from uniform and nonuniform initial concentration distributions across the stem radius were compared with steady-state experimental data. With known values of plant stem radius, water usage, water content, and the distance over which the concentration decreased by 50%, the diffusion coefficient of MTBE radial transport across the plant stem was estimated with 95% confidence to be in the range of 8.43-16.2 × 10 -8 cm 2 /s with a mean of 1.23 × 10 -7 cm 2 / s. When the diffusion coefficient was calculated based on transient experimental data, the values with 95% confidence interval ranged from 4.14 x 10 -7 to 8.00 x 10 -7 cm 2 /s with a mean value of 6.07 x 10 -7 cm 2 /s. The difference between these two results can be reduced by more accurate estimation of the water flow velocity through plant stems. The model is applicable to other species including sunflowers and poplars upon substitution of appropriate parameters.

Experiments in a laboratory chamber were used to investigate the influence of alfalfa plants on the fate and transport of trichloroethylene (TCE) fed at a concentration of 200 μl/L (~290 mg/L) in the entering groundwater. The dimensions of the chamber were 180 cm in axial length, 35 cm in depth and 10 cm in width. Concentrations of TCE were monitored in the aqueous and gas phases. Evapotranspirational fluxes of TCE from the soil to the headspace of the chamber were also measured. TCE concentration in the solid phase was measured as a function of depth. Mathematical modeling of the fate of TCE was developed assuming rate-independent physical equilibrium partitioning between solid, aqueous, and gas phases. The model included volatilization across a thin atmospheric boundary layer near soil surface. Numerical results were first validated with analytical results for simple cases and then compared with experimental data in the chamber. Results indicated that the water content and air content distribut...

Vegetation can enhance in situ bioremediation processes in many applications. Microbial transformations occur in soil and water external to plant roots. Organic contaminants also enter vegetation and are transformed within plants. Research progress is reviewed with emphasis on recent experimental results and mathematical models of contaminant fate in systems where vegetation is present. Plant evapotranspiration provides a solar driven pump-and-treat system which moves contaminants to the rhizosphere and helps to contain them on site. Significant savings have been reported at several field sites where vegetation has been utilized.

The strong sorption of hydrophobic contaminants poses a serious challenge to the development of remediation technologies. Their low solubilities in water limit the applicability of treatment technologies such as pump-and-treat. Their dissolution by surfactants is a promising approach for circumventing this difficulty. The solubilized contaminant is subsequently irrigated onto a vegetated zone and mineralized. A two-zone model is developed for a system in which the contaminant is flushed from the aquifer with an aqueous surfactant solution and applied to vegetated soil. The model takes into account dissolution, sorption and biodegradation of the contaminant in the aquifer zone under the assumption that local equilibria prevail. It also takes into account sorption, mineralization and plant uptake in the rhizosphere zone assuming that mineralization obeys Monod kinetics. Model simulation was performed to determine the effects of surfactant and oxygen concentrations in enhancing contaminant removal from the aquifer and to evaluate the number of flushings required to reduce the concentrations of contaminant to desired levels. The results indicate that surfactant appreciably reduces the number of flushings by increasing the solubilization of contaminant. Increasing oxygen concentration enhances contaminant degradation. The model predicts an optimistic outcome because of the assumptions imposed; it is expected that the actual number of flushings will be larger than predicted.

Aerated reactors are widely used in cell culture processes. The bubbles that are introduced into such reactors provide essential mixing and oxygen, but the disengagement of those bubbles can result in the imposition of undesirable stresses upon fluid-borne cells. This occurs because some of the energy associated with interfacial tension is converted to high-velocity motions in the form of film rupture, droplet ejection and bubble cavity collapse. Obviously these effects would be amplified if there was an affinity between the cells and the gas-liquid interface. The present work was carried out in an effort to better characterize the energy, frequency of occurrence, and periodicities of these phenomena. This investigation examined the effects of fluid (medium) properties, bubble size, and gas rate upon both film and jet droplet ejection processes, as well as upon pressure disturbances measured at the reactor wall just beneath the free surface

Every hour, the sun emits more energy onto the Earth's surface than our entire world population uses in one year (Green Fuel, 2013, http://www.greenfuelsolar.com/solar-fact-or-fiction/) Solar power provides us with the possibility of a cleaner and more renewable future. Global climate change as a result of greenhouse gases and the effects of low air quality caused by pollutants have become very substantial issues in our world today. The costs associated with greenhouse gas and air pollutant emissions, and the effect they have on human lives and human health, are major and growing concerns. The development and installation of solar powered charging stations will reduce the amount of greenhouse gases emitted into the atmosphere, future costs associated with climate change, and health issues. Thus, there is environmental, social, and economic value associated with the installation of solar powered charge stations. Solar powered charging stations have the potential of significantly reducing air pollutants and improving urban air quality. The electrification of transportation and the use of solar powered charging stations as an electricity source will improve people's quality of life. © 2013 American Institute of Chemical Engineers Environ Prog, 33: 1298–1308, 2014

The growing interest in algae is associated with current commercial products and future potential biofuel developments. The focus of this chapter is on commercial products from microalgae and macroalgae. This market is estimated to be of the order of billions of dollars per year with more than 20 different commercial products. The largest market is food products, including nutraceuticals and functional foods. There are many refined products; in some cases, there are multiple product streams associated with the separation process. Production occurs in fresh water for some microalgae such as Spirulina. Many macroalgae are grown in salt water environments; there are both managed production systems and harvests from natural areas of seas and oceans. Because of the diversity of growth environments and species, many more potential products are possible, and additional research is to be encouraged. There are many additional locations in the world that can be used to produce beneficial products.

Experiments were conducted to investigate the fate of ethylbenzoate and soil microorganisms in shallow aquifers. Biodegradation and volatilization have been identified as the major mechanisms in attenuating ethylbenzoate in contaminated soils. The rate of volatilization was experimentally found to be limited by gas-phase diffusion. The parameters of an available model, i.e., the maximum specific growth rate and the saturation constant, have been estimated by fitting the model to the experimental data obtained with ethylbenzoate as the carbon source; the former was 0.49 h−1, and the latter was 62 mg L−1. Various facets of biodegradation, including the effects of mass-transfer resistance and initial distribution of microorganisms, have been numerically analyzed on the basis of the model.

In-situ bioremediation is a process by which contaminants in subsurface environments are biologically eliminated or mineralized; however, it is often difficult to implement. Microbes sparsely distributed in deep soils are incapable of degrading a chemical rapidly; furthermore, fine-pore structures of soils tend to retard the penetration and propagation of these microbes and hinder oxygen transfer. The latter is particularly detrimental to the aerobic growth of microbes, which is often essential for bioremediation. Measures intended to promote bioremediation, such as the addition of surfactants for enhancing dissolution and the application of genetically engineered microbes for accelerating the biodegradation of contaminants, are almost impossible to adopt. This is attributable to the fact that various facets of the bioremediation process (e.g., the distribution of dissolved contaminants, nutrients, and oxygen, and the concentration of microbes) cannot be readily manipulated. This article proposes a novel technology, namely, bio-wall. This technology resorts to an in-situ constructed medium with porosity and organic content greater than those of the original soil for promoting the adsorption and retention of microbes and the biodegradation of contaminants. Moreover, oxygen and nutrients are supplied to the bio-wall to facilitate microbialgrowth. The results of conceptual design study and simulation have revealed that the technology is indeed feasible and, under certain environmental conditions, cost-effective. Particularly noteworthy is the fact that bio-wall can prevent contaminant migration through the enhancement of the biodegradation rate and reduction of the plume-distance, both by several orders of magnitude.

The widespread release of organic chemicals in the environment frequently leads to groundwater contamination with non-aqueous phase liquids (NAPLs) because many of these organic chemicals are barely soluble in water. Understanding the mechanisms of transport and biotic transformation is essential for successful design and implementation of remedial strategies for contaminated soils. A model describing the biodegradation of the contaminants in NAPL-groundwater systems has been developed in this paper. Numerous field data and experimental results have indicated that the non-wetting fluids of the NAPLs in groundwater are trapped, i.e., completely surrounded by the wetting aqueous phase. In the present model, therefore, the NAPLs are treated as discrete blobs, while the aqueous phase is considered to be continuous. Interactions between the two liquid phases are incorporated into the governing equations for the aqueous phase. The rates of dissolution and desorption are assumed to be of the first order. Only aerobic growth of microorganisms is taken into account. This paper focuses on situations in which dissolution is the main rate-limiting factor. An investigation has been carried out on the rates of biodegradation of some common petroleum components such as benzene, ethyl-benzene, toluene, and xylene in the four-phase system. The effects considered are those of the mass-transfer area, specific growth rate of biomass, and velocity of pore-water flow.

Methane is the main component of natural gas and has been connected with global warming. The oxidative coupling of methane has been studied to enhance C2 hydrocarbon selectivity and to reduce the formation of carbon oxides associated with C2 hydrocarbon production. Acid sites of supported catalysts play a role in the formation of carbon oxides. The supported Zn oxide catalyst with α-Al2O3 shows no acidity in temperature programmed desorption by using NH3 and exhibits good C2 hydrocarbon selectivity. The optimum loading of Zn oxide on α-Al2O3 is 60 wt%. The specific surface area of the catalyst appears not to influence activity. Using alkali metal salts as promoter in Zn oxide (60 wt%)/α-Al2O3 catalyst, the activity performance for C2 hydrocarbon formation is LiCl > NaCl > KCl: the performance is well correlated with the apparent molal enthalpy of formation of halides. The activity performance for minimizing carbon oxides is LiCl > KCl > NaCl, which is well correlated with the melting points in alkali halides.

Experimental investigations were carried out in the laboratory to study the impact of vegetation in bioremediating soil and groundwater contaminated with hazardous organic substances. A chamber consisting of two U-shaped channels, each 1.8 m in length, 10 cm in width, and 35 cm in depth, was set up. The channels were packed with fine sandy soil collected from near a landfill. Alfalfa plants were grown in the channels under laboratory conditions for nearly two years. The water fed to the plants in one channel was contaminated with toluene solution at saturated concentrations at 26°C. Plants in the other channel were fed with water contaminated with phenol solution at 500 ppm (v/v). The contaminant concentrations in the groundwater were monitored at sampling wells located along each of the channels. The influent and effluent flow rates from each channel were recorded daily. Evapotranspiration significantly influenced the fate of the pollutants. Dispersion and adsorption processes in the channel were studied separately, by introducing bromide tracer as a broad pulse into the toluence fed channel, and by observing the washout of toluene and phenol contaminants following a feed step change to pure water. Tracer studies indicated that short-circuiting at the U-bend of the channel was quite significant. Previously developed models which described the fate of contaminants in variably-saturated soils in the presence of vegetation are employed to simulate the fate of these hazardous organic substances in the laboratory chamber.

The microbial biodegradation of xenobiotic compounds in soil and ground water is constrained by the laws of thermodynamics. Bioremediation is being investigated in a rhizosphere environment in which higher plants provide carbon and energy to sustain the microbial population. Toluene, phenol, trichloroethylene and trichloroethane have been fed in separate experiments to a pilot scale system with alfalfa growing in sandy soil containing less than 10% of silt. It is well known that microbial populations are numerous in the root zone of healthy vegetation. Root exudates can stimulate aerobic microbial biodegradation of compounds which by themselves support growth poorly or not at all. Polynuclear aromatic compounds such as phenanthrene, anthracene, and pyrene, which are not very soluble in water, and chlorinated aliphatic hydrocarbons such as trichloroethylene are examples of compounds that can be biodegraded in the rhizosphere when root exudates are present to enhance and sustain microbial activity. Solar driven transport processes such as water and solute movements due to evapotranspiration increase the likelihood that the contaminants will come into contact with the microorganisms and be degraded. The thermodynamic and bioenergetic aspects of transport and biodegradation in the rhizosphere are examined through a review of the literature and the analysis of experimental data collected in the pilot scale system.

The fate of two volatile organo chlorinated compounds, 1,1,1-trichloroethane (TCA) and trichloroethylene (TCE), was studied in rhizosphere soil. Laboratory experiments were performed with alfalfa (Medicago sativa) growing in sandy silt soil fed continuously with groundwater contaminated with TCA and TCE at 50 and 200 μL/L, respectively. Methane generated in the groundwater provided evidence for anaerobic biodegradation. Groundwater samples indicated that the concentration of TCE decreased with axial position during the steady-state period. The flow rate of the effluent was significantly less than the inlet flow because of active evapotranspiration. Thus, a significant fraction of TCA and TCE disappeared. Headspace analysis of the gas in the enclosed chamber using a FT-IR spectrophotometer showed that small quantities of TCA and TCE migrated into the gas phase above the alfalfa plants ; no chlorinated intermediates or methane were found in this gas phase.

Simple regression analysis is based on the least square of residual errors. To use this method, an independent variable which is observable without error is assumed to exist. For most analyses, the assumption is normally made without realising the implications. The present study demonstrates how parameters may be estimated with the assumption of error in all measurements. Data sets involving batch/fed-batch cultivation of Candida utilis were analysed using a statistical approach with error in variables for the estimation of true biomass energetic yield and maintenance coefficient. This approach requires replicated measurements. For linear systems, such as in chemical/biochemical processes, replicated measurements are sometimes possible or there are physical/physiological reasons to group the observations into clusters. When clusters of replicated measurements are not available, the cluster analysis technique may be used to identify groups of near-replicated data points. The procedure yielded similar results to those obtained by the ordinary least squares procedure for consistent data. However, for data of poor quality (especially data with large errors in the independent variable), the disparity between the two procedures was more significant.

Environmental contaminants are frequently encountered as mixtures of non-aqueous phase liquids (NAPLs). The dissolution of organic mixtures from the aquifer has been examined with and without biodegradation. Various physical processes involved have been quantified based on the assumptions that liquid-liquid and sorption equilibria are established at the beginning of each flushing; oxygen required for biochemical oxidation is completely consumed by the end of each flushing; and the rate of biochemical oxidation obeys the Monod kinetics for a multi-substrate system, characterized by an oxygen utilization factor. The mass fraction of any component remaining in the aquifer, its aqueous concentration, and the composition of the NAPL have been obtained as functions of the number of flushings (volume of the flushing solution/volume of the aqueous-phase voids). The results of the simulation with the model demonstrate that highly soluble components of the NAPL are mainly removed by the pump-and-treat mechanism while the components of extremely low solubility are unavailable to the microbes as substrates in a multi-component scenario. Bioremediation, however, transforms a significant proportion of the low solubility compounds after the more soluble components have been removed from the aquifer. The results also demonstrate that the rate of removal of compounds is retarded by the inclusion of a non-soluble component in the mixture.

Interfacial phenomena frequently give rise to energetic fluid motions in the culture of plant and animals cells, and these motions may result in loss of cellular viability. Bubble disengagement processes have often been the center of attention in this regard. Recent work has shown, however, that surprisingly large interfacial velocities can be generated in aqueous solutions of glycerol by an elongation-retraction mechanism occurring just above the orifice following bubble formation at sieve-plate spargers. While it is evident that this process can occur under a variety of conditions, it is now clear that certain combinations of hole size, gas rate, and medium viscosity result in unusually energetic interfacial motions. An extensive investigation of this phenomenon has been completed, involving both the collection of experimental data and hydrodynamic modeling; this work has shown that shear stresses can be generated by this process that may be as large as 2000 to 3000 dynes/cm2 in 50% glycerol so...

Studies were conducted in a Thai poultry plant to identify the factors that affected numbers of Campylobacter jejuni in chicken carcasses. The concen- trations of Campylobacter were determined using the SimPlate most probable number and modified char- coal cefoperazone deoxycholate plating methods. Re- sults indicated that the mean concentrations of C. je- juni in carcasses after scalding, plucking, and chilling were 2.93 ± 0.31, 2.98 ± 0.38, 2.88 ± 0.31, and 0.85 ± 0.95 log cfu, whereas the concentrations of C. jejuni in the scalding tank water, plucked feathers, and chicken breast portion were 1.39 ± 0.70, 3.28 ± 0.52, and 0.50 ± 1.22 log cfu, respectively. Sensitivity analysis using tornado order correlation analysis showed that risk pa- rameters affecting the contamination of C. jejuni in the chicken slaughter and processing plant could be ranked as chilling water pH, number of pathogens in the scald tank water, scalding water temperature, number of C. jejuni on plucked feathers, and residual chlorine in the chill water, respectively. The exposure assessment and analysis of process parameters indicated that some of the current critical control points were not effective. The suggested interventions included preventing fecal contamination during transportation; increasing the scalding temperature, giving the scalding water a high- er countercurrent flow rate; reducing contamination of feathers in the scalding tank to decrease C. jejuni in the scalding water; spraying water to reduce contamination at the plucking step; monitoring and maintaining the chill water pH at 6.0 to 6.5; and increasing the residual chlorine in the chill water. These interventions were recommended for inclusion in the hazard analysis and critical control point plan of the plant.

Bioreactors are vessels that have been designed and produced to provide an effective environment for enzymes or whole cells to transform biochemicals into products. In some cases, inactivation of cells or sterilization is carried out in the bioreactor such as in water treatment. Many different bioreactors and bioreactor applications are described, including those for cell growth, enzyme production, biocatalysis, food production, milk processing, extrusion, tissue engineering, algae production, protein synthesis, and anaerobic digestion. Methods to classify bioreactors are presented, including operational conditions and the nature of the process. References are included to enable the reader to find more information on each of the types of bioreactors and selected products. The emphasis is on reactors that are produced commercially rather than on reactors that have evolved in the natural world. Bioreactors used for DNA and protein synthesis (biomolecular synthesizers) are included. Commodity products include all substances that are produced in bioreactors and marketed; however, the emphasis is on general principles and more widely used bioreactor types and products.

Sensory studies have been conducted on flavored soy yogurt (FLAVSYO) and frozen flavored soy yogurt (FROZSYO) made from rapid hydration hydrothermal cooked soy milk. Trained panel testing was conducted with a panel of 5. Consumer acceptance tests were carried out with 195 consumers using standard nine-point hedonic scales. The frequencies of the consumers who liked FROZSYO were high at like slightly to like extremely, the FLAVSYO and FROZSYO had less beany flavor than the soy milk. The data from the trained panel indicate that processing, fermentation, and flavoring significantly changed the major attributes. Relative to unflavored soy yogurt, the beany flavors, chalkiness, aftertaste, sweetness, uniformity, and mouth coating scores of the FLAVSYO and FROZSYO were closer to the corresponding sensory scores for the commercial yogurt.

Soy milk samples produced from 11% soybean slurry cooked by the rapid hydration hydrothermal cooking (RHHTC) process at temperatures from 105-157C for 24-90 s were studied for their sterility, microbiological quality, flatulent sugar reduction, and physical characteristics. Soy milk produced at the temperature of 132C, or higher, for 29 s or longer was sterile. All of the bacteria (Pseudomonas aeruginosa, Serratia lequefaciens, S. rubidaea, and Enterobacter cloacae including the bacilli cells and spores) were destroyed completely. At lower temperatures, 105-127C, the Gram negative bacteria were destroyed; however, the spores of Bacillus licheniformis and B. cereus, Gram positive bacteria survived the heat. Temperatures of 143-157C with a retention time of soy slurry solids in the holding tube of 30 s or longer are recommended to sterilize the product. the mean residence time of soy solids processed by the RHHTC unit was 30 s.

Plants have the potential for aiding in situ remediation of contaminated soil and groundwater by promoting microbial growth in the rhizosphere. Microbial populations vary in response to the presence of oxygen, water and metabolizable carbon sources. Plants are able to provide a favorable environment for microbe growth by providing a plant pathway for oxygen transfer to the soil, transferring water from saturated to unsaturated soil, and supplying supplemental substrate in the form of root exudates and decaying root hairs. Models of the physical, chemical, and biological relationships in the rhizosphere are reported. Simulation results are presented for a hypothetical vegetative buffer zone over a shallow aquifer. The fate of atrazine is simulated in order to investigate the effects of rainfall, evapotranspiration, atrazine uptake by plants, and atrazine adsorption to root surfaces on atrazine concentration at the downstream edge of the vegetative buffer zone.

The use of plants in remediation of soil and unconfined groundwater contaminated with organic materials is appealing for a variety of reasons: (1) plants provide a remediation strategy that utilizes solar energy; (2) vegetation is aesthetically pleasing; (3) plant samples can be harvested and tested as indicators of the level of remediation; (4) plants help contain the region of contamination by removing water from soil; (5) rhizosphere microbial communities are able to biodegrade a wide variety of organic contaminants; and (6) many plants have mechanisms for transporting oxygen to the rhizosphere. However, before effective plant remediation strategies can be developed, an understanding is needed of the physical, biological, and chemical relationships that determine the fate of each organic contaminant in the rhizosphere. This review presents an overview of some factors required to understand and model the complex processes that determine the fate of the organic contaminants in plant remediation ...

The shear sensitivity of animal and plant cells is a problem often encountered in large-scale cell culture. Such sensitivity varies with different cell lines and the severity of cellular damage may depend on both the magnitude and the duration of the shear stress. In a bioreactor, the shear susceptibility of cells depends on their response to hydrodynamic forces arising from fluid motions of particular scale. Cell damage may be induced by forces in the bulk liquid phase, but fluid motions associated with the gas-liquid interface are especially energetic. The detrimental effects of hydrodynamic forces are abated by the addition of some polymers, such as Pluronic F-68, methylcellulose, or serum; the exact mechanisms of protection are the subject of current research.

In Kazakhstan, a deepening ecological crisis has been caused by contamination of the environment with obsolete and expired pesticides. Large-scale physical and chemical technologies for managing pesticide-contaminated soils are expensive and unacceptable for Kazakhstan because of limited financial resources. Phytoremediation is a promising innovative technology for managing pesticide-contaminated soils. Pesticide contamination is common on land surrounding destroyed warehouses that were part of the official plant protection service of the former Soviet Union.

PREFACE 1. Review of Nanoscale Materials in Chemistry: Environmental Applications KENNETH J. KLABUNDE, LARRY ERICKSON, OLGA KOPER, AND RYAN RICHARDS 2. Size-Dependent Properties and Surface Chemistry of Oxide-Based Nanomaterials in Environmental Processes VICKI H. GRASSIAN 3. Nanoparticle Solutions C. M. SORENSEN 4. Chemistry of Rocksalt-Structured (111) Metal Oxides APRIL CORPUZ AND RYAN RICHARDS 5. Selected Environmental Applications of Nanocrystalline Metal Oxides SLAWOMIR WINECKI 6. Mesoporous Titanium Dioxide DAN ZHAO, SRIDHAR BUDHI, AND RANJIT T. KOODALI 7. Decontamination of Chemical Warfare Agents with Nanosize Metal Oxides GEORGE W. WAGNER 8. Advanced Lubricant Additives of Dialkyldithiophosphate (DDP)-Functionalized Molybdenum Sulfide Nanoparticles and Their Tribological Performance for Boundary Lubrication DMYTRO DEMYDOV, ATANU ADHVARYU, PHILIP MCCLUSKEY, AND AJAY P. MALSHE 9. Environmental Applications of Zerovalent Metals: Iron vs. Zinc PAUL G. TRATNYEK, ALEXANDRA J. SALTER, JAMES T. NURMI, AND VAISHNAVI SARATHY 10. Visible and UV Light Photocatalysts in Environmental Remediation KENNETH J. KLABUNDE 11. Heterogeneous Photocatalysis over High-Surface-Area Silica-Supported Silver Halide Photocatalysts for Environmental Remediation DAMBAR B. HAMAL AND KENNETH J. KLABUNDE 12. An Inorganic Oxide TiO2-SiO2-Mn Aerogel for Visible-Light Induced Air Purification KENNEDY K. KALEBAILA AND KENNETH J. KLABUNDE 13. Comparative Pulmonary Toxicity of Metal Oxide Nanoparticles J. A. PICKRELL, D. VAN DER MERWE, L. E. ERICKSON, K. DHAKAL, M. DHAKAL, K. J. KLABUNDE, AND C. SORENSEN 14. The Development of FAST-ACT by NanoScale Corporation OLGA B. KOPER 15. Nanoscale Catalysts and In Room Devices To Improve Indoor Air Quality and Sustainability STEVE ECKELS, OLGA B. KOPER, LARRY E. ERICKSON, AND LYNETTE VERA BAYLESS INDEXES AUTHOR INDEX SUBJECT INDEX

Rational design of airlift reactors for the culture of plant and animal cells is impeded by a lack of understanding of the causes of loss of viability. Some recent speculations in the literature suggest that gas-liquid interfacial phenomena have played prominent roles in observed instances of loss of viability in both insect and animal cell cultures. The important interfacial events may include bubble formation and detachment at the sparger, bubble coalescence and breakage, and bubble disengagement at the free surface-entailing film thinning, film rupture, and film droplet ejection. We have carried out an experimental investigation of interfacial phenomena using macrovideography and acoustic signals recorded at both the sparger and the free surface. Data have been collected for several liquid media including distilled water, distilled water with electrolyte (NaCl), and aqueous solutions of glycerol (μ = 3 to 9.5 cP). The studies were conducted in a 3-liter, acrylic plastic, split-column airlift r...

The dermal absorption potential of a nanocrystalline magnesium oxide (MgO) and titanium dioxide (TiO(2)) mixture in dermatomed human skin was assessed in vitro using Bronaugh-type flow-through diffusion cells. Nanocrystalline material was applied to the skin surface at a dose rate of 50 mg/cm(2) as a dry powder, as a water suspension, and as a water/surfactant (sodium lauryl sulfate) suspension, for 8 hours. Dermal absorption of nanocrystalline MgO and TiO(2) through human skin with intact, functional stratum corneum was not detectable under the conditions of this experiment.

New technologies are not only critical in supporting military and industrial success, but also play a significant role in advancing sustainable development. With the current global economic challenges, effective tools and partnerships which streamline the design and dissemination of these technologies are more important than ever. Accordingly, the systems environmental engineering approach utilized by the Urban Operations Laboratory (UOL), [comprised of M2 Technologies, Kansas State University, and CABEM Technologies], has facilitated innovative research, training, assessment, and product design for DoD and other stakeholders. Through strategic life-cycle environmental assessments (LCEA); programmatic environment, safety, and occupational health evaluations (PESHE); Health Hazard Assessments; and other proactive studies and reports, UOL has helped foster successful development and deployment of non-lethal technologies. More specifically, these efforts provide a framework for addressing complex environment, safety, and occupational health (ESOH) risks that affect personnel, infrastructure, property, and natural/cultural resources. Integrated analyses (comprehensive and transdisciplinary) involving flexible groups of subject matter experts, are employed in support of public and private collaborations with a focus on inputs, hazards, and constraints. This paper highlights the UOL process which can translate into advantages for a variety of projects (e.g., environmental, water, energy, infrastructure, etc.).

The role of aggregates and their characteristics on bioremediation in soil has received very little attention. In this investigation, the contaminated aggregates bioremediation (CAB) model has been developed and simulated to analyze the bioremediation of soil and water in the aggregates. The model equations consist of a system of three non-linear partial differential equations. Dimensional analysis of the equations has been performed. Sensitivity analysis conducted by numerically solving them has demonstrated the effects of aggregate radius, partition coefficient, and initial contaminant concentration on the time and mechanism of remediation. The rates of diffusion of substrate and oxygen, and the biodegradation-rate have been found to be the controlling mechanisms for remediation in the aggregates.

Understanding the dynamic phenomena of viability loss of shear sensitive cells and bubble breakage and coalescence within airlift reactors requires knowledge of local, liquid-phase hydrodynamics. The laser-Doppler velocimeter (LDV) is a non-invasive instrument which may be used to obtain this information. Experimental procedures and software were developed to detect and measure Doppler bursts in two-phase flow in a split-cylinder airlift reactor. Off-line analysis of the data indicated a detection rate approximately one order of magnitude greater than that observed using an available commercial frequency tracker. Approximately 400 to 500 observations are needed for the ensemble mean to characterize the local mean velocity to within ±5% for a superficial gas velocity of 10.4 cm/s, the highest superficial gas velocity used in these studies. The limitations, prospects, and signal-processing options for LDV in this application are also discussed

Typical yogurt bacteria, Lactobacillus bulgaricus and Streptococcus thermophilus, have been studied for their ability to utilize stachyose and other sugars in soymilk. Subculturing of the inocula on nonfat dry milk powder (NFDM) yielded bacteria that displayed oligosaccharide formation during fermentation of soymilk. However, storage of stock cultures on soymilk for 168 h or longer resulted in stachyose hydrolysis during fermentation. Values of the maximum specific growth rate for mixed cultures of Lactobacillus bulgaricus and Streptococcus thermophilus grown on soymilk at 44°C were estimated using the covariate adjustment method which allows biomass, substrate, and product data to be employed, simultaneously. Point estimates were 0.341, 0.296, and 0.478 h−1 for soymilk fermentation by inocula subcultured on 11% NFDM, for inocula stored in soymilk for greater than 168 h, and for inocula prepared as a mixed culture, respectively. the available electron balance (A.E.B.) was employed to check the consistency of the data using biomass, substrate and product measurements.