Personal Research Database

Full Text: J\J Haz Mat38, 439.pdf

Abstract: Extensive experiments were performed to investigate the adsorption (equilibrium) isotherms of cadmium on activated carbon in the presence of the following chelating agents: ethylenediaminetetraacetic acid (EDTA), citric acid and nitrilotriacetic acid (NTA). The extent of adsorption was found to be a function of solution pH and cadmium chelate species distribution. A relationship between pH and the parameters of the Freundlich and Langmuir models is discussed. Reprinted by permission of the Publisher.

? Watts, R.J., Kong, S., Dippre, M. and Barnes, W.T. (1994), Oxidation of sorbed hexachlorobenzene in soils using catalyzed hydrogen-peroxide. Journal of Hazardous Materials, 39 (1), 33-47.

Full Text: 1994\J Haz Mat39, 33.pdf

Abstract: The Fenton-like oxidation of a highly hydrophobic and biorefractory compound, hexachlorobenzene, was investigated in silica sand and a natural soil using a number of process conditions including catalysis by soluble iron and naturally-occurring iron minerals coupled with a range of hydrogen peroxide concentrations from 3 mM to 300 mM (100 mgl^-1 to 100000 mgl^-1). In addition, hexachlorobenzene desorption rates were quantified and compared to the rates of oxidation. Using soluble iron and peroxide concentrations greater-than-or-equal-to 100 mM, sorbed hexachlorobenzene was oxidized more rapidly than the measured desorption rate, indicating that it may have been, in part, oxidized on the surface of the silica sand. The results suggest that hydroxyl radicals may cross the liquid-solid interface under aggressive reaction conditions. Alternatively, the aggressive Fenton-like reaction conditions may alter the hexachlorobenzene sorption characteristics and increase its rate of desorption resulting in an enhanced coupled desorption-oxidation mechanism. In the second phase of study using natural iron minerals as the catalyst, hexachlorobenzene was oxidized more slowly than it was desorbed. The probable mechanism for mineral-catalyzed oxidation is desorption followed by oxidation through a Fenton-like process at the mineral surface. In the treatment of a natural sandy loam soil, hexachlorobenzene was oxidized at rates slower than it was desorbed. The most efficient process condition (mineral-catalyzed oxidation) was optimized using a central composite rotatable factorial design analysis. These experiments showed that maximum hexachlorobenzene removal occurred with H₂O₂ concentrations of 3 to 5 mM and slurry volumes of 25 to 30 times the field capacity of the soil.

Keywords: Aggressive, Analysis, Capacity, Catalyst, Composite, Contaminated Soils, Degradation, Design, Desorption, Experiments, Factorial Design, Fenton Like, Fenton Reagent, Fenton-Like, H₂O₂, Hexachlorobenzene, Hydrogen Peroxide, Hydrophobic, Hydroxyl Radicals, Iron, Mechanism, Natural, Oxidation, Process, Removal, Sand, Silica, Soil, Soils, Sorption, Surface, Treatment, Water

? Gandhi, P., Erickson, L.E. and Fan, L.T. (1994), A simple method to study the effectiveness of bioremediation aided, pump-and-treat technology for aquifers contaminated by nonaqueous phase liquids. 1. Single-component systems. Journal of Hazardous Materials, 39 (1), 49-68.

Full Text: 1994\J Haz Mat39, 49.pdf

Abstract: Various physical processes occurring during the dissolution and biodegradation of non-aqueous phase liquids (NAPLs) have been quantified based on the local-equilibrium assumption involving liquid-liquid equilibrium, sorption equilibrium and biochemical reaction equilibrium. The mass fraction of contaminant remaining in the aquifer and the aqueous concentration of the contaminant have been obtained as functions of the number of flushings (volume of the flushing solution/aqueous phase void volume). The present simplistic approach illustrates that bioremediation can significantly reduce the remediation period for sites contaminated by the NAPLs. Bioremediation is recommended as a ‘polishing step’ to remove the trace contaminants not readily removed by the flushing process. The proposed model should provide a useful bound regarding the efficiency of bioremediation aided, pump-and-treat technology. The actual number of flushings may exceed the values reported here.

Keywords: Biodegradation, Bioremediation, Contaminant, Contaminants, Degradation, Dissolution, Efficiency, Equilibrium, Flushing, Fraction, Hydrogen-Peroxide, Intraparticle Diffusion, Mass-Transfer, Model, Non-Aqueous Phase, Polishing, Process, Remediation, Soil, Sorption, Technology, Transport, Trichloroethylene, Values

Brown, J.P. and Fan, A.M. (1994), Arsenic: Risk assessment for California drinking-water standards. Journal of Hazardous Materials, 39 (2), 149-159.

Full Text: J\J Haz Mat39, 149.pdf

Abstract: Six California counties contain 15 water systems with arsenic concentrations above the 50 ppb Maximum Contaminant Level (MCL). Arsenic compounds are carcinogenic in humans by oral and inhalation routes. They are also fetotoxic and teratogenic in mice, rats and hamsters and cause a variety of toxic effects in the gastro-intestinal tract, circulatory system, skin, liver, kidney, nervous system and heart. The US EPA has identified an oral human chronic No-Observable-Adverse-Effect Level (NOAEL) of 0.0008 mg/kg-d based on akin and vascular effects. In 1988 EPA estimated the human carcinogenic potency of arsenic in drinking water to be about 2×10^-3/ µg/kg-d with a 10^-6 lifetime skin cancer risk equivalent to consumption of 21/day at 20 ppt. Recently Smith et al. (1990) estimated the potency of arsenic to be 5.3×10^-3/ µg/kg-d based on the same human data. Also Chen et al. (1988) and Chen and Wang (1990) identified the additional tumor sites of liver, lung, bladder, kidney, nasal cavity and prostate. The lifetime risk of developing skin cancer at the 50 ppb MCL level (21/day) is about 8 in 1000. Preliminary analysis of the recent data on other tumor sites indicate comparable risks of: females-lung, 11.0; bladder, 6.7; kidney, 3.4; liver, 0.3; males-lung, 6.1, bladder, 2.2; kidney, 1.4; iver, 0.2. On the basis of a skin cancer potency of 5.3×10^-3/ µg/kg-d, a Recommended Public Health Level (RPHL) of 2 ppt (0.002 µg/l) is being proposed in accordance with the provisions of the Safe Drinking Water Act of 1989. This value assumes a body weight of 70 kg, a water consumption of 21/day, a relative source contribution of 20%, and a lifetime extra cancer risk of 10^-6.

Keywords: Disease Endemic Area, Malignant Neoplasms, Well Water, Environmental Risks, Northern Sweden, Cancer, Smelter, Taiwan, Lung

? Fowler, G.D., Sollars, C.J., Ouki, S.K. and Perry, R. (1994), Thermal conversion of gasworks contaminated soil into carbonaceous adsorbents. Journal of Hazardous Materials, 39 (3), 281-300.

Full Text: 1994\J Haz Mat39, 281.pdf

Abstract: Contaminated soil from a gaswork site has been successfully converted into a carbonaceous adsorbent utilising ZnCl₂ as an activating agent. The organic contamination, consisting of coal tars, phenols and associated compounds, was converted into a carbonaceous material. Extensive reduction (95%) in the cyanide content of the soil after treatment was observed and entrapment of metallic contamination within the carbonaceous matrix has been observed through XRF analysis. Surface area and porosity analysis by gas adsorption indicates surface areas ranging from 110 to 570 m²/g, and development of microporosity within the carbons. The complex contamination within the soils has influenced the development of adsorption characteristics within the samples, and sulphur, in particular, appears to play a major part in the development of this.

Keywords: Activated Carbon, Adsorbent, Adsorption, Agent, Analysis, Chemical Activation, Coal Pyrolysis, Contamination, Cyanide, Development, Low-Cost Adsorbent, Microporosity, Phenols, Play, Porosity, Reduction, Samples, Selection, Soil, Soils, Spent Bleaching Earth, Surface, Treatment, Xrf, Zinc-Chloride, ZnCl₂

Yang, G.C.C. and Chen, S.Y. (1994), Statistical analyses of control parameters for physicochemical properties of solidified incinerator fly ash of municipal solid wastes. Journal of Hazardous Materials, 39 (3), 317-333.

Full Text: J\J Haz Mat39, 317.pdf

Abstract: In this work, statistical analyses of control parameters for various physical and chemical properties of solidified incinerator fly ash of municipal solid wastes were conducted. Fly ash obtained from a domestic garbage incinerator was solidified by a cement-based technique. The solidification recipes employed were following the L9 orthogonal arrays of the Taguchi method. ASTM Type I portland cement, mixing water, incinerator fly ash, and partial replacement of cement by water-quenched blast furnace slag or addition of a modified lignosulphonate to cement paste were used as experimental factors accompanied by three levels of variation for each experimental factor. Experimental results showed that solidification indeed yielded solidified monoliths with satisfactory physicochemical properties such as unconfined compressive strength, TCLP leaching toxicity, and acid neutralization capacity. These measured values of various properties then were subjected to the variance analysis for determining the respective degree of contribution for each experimental factor and the regular analysis for determining the response value for each corresponding variation level. The findings are discussed in this paper.

? Nakhla, G.F. and Suidan, M.T. (1994), Effect of process variables on the treatment of toxic wastewaters with anaerobic GAC reactors. Journal of Hazardous Materials, 39 (3), 335-350.

Full Text: 1994\J Haz Mat39, 335.pdf

Abstract: The expanded-bed anaerobic GAC reactor, operating with GAC replacement, was demonstrated to effectively treat hazardous wastes. This study investigated the effects of GAC replacement rates, organic loading, and hydraulic retention time (HRT) on the treatment efficiency of an inhibitory wastewater. A synthetic toxic wastewater containing 5 g/l acetic acid, 3 g/l phenol and 0.9-1.8 g/l ortho-cresol was fed at a constant flow rate to three anaerobic GAC reactors, two of which were operated at an unexpanded empty-bed HRT of 1.0 d and the third at a HRT of 0.5 d. The reactors affected more that 97% COD removal throughout the study. Excellent treatment of the toxic waste was accomplished at GAC mean residence times as low as 8 d, and at COD loading rates of 35 kg/m3-d. The reactors converted over 90% of the biodegradable influent COD to methane gas at high GAC residence time. The methane conversion efficiency dropped to about 64% in the reactors operated at a HRT of 1.0 d and 80% in the reactor operated at a HRT of 0.5 d at GAC residence times of 8 d. The GAC replacement rates were sufficient to overcome the toxicity of ortho-cresol. Organic loading rates and HRT appeared to adversely influence process performance, particularly when phenol was predominantly removed by biodegradation.

Keywords: Acetic Acid, Acid, Adsorption, Anaerobic, Biodegradation, COD, COD Removal, Efficiency, GAC, HRT, Influence, Performance, Phenol, Process, Removal, Replacement, Retention, Third, Toxicity, Treatment, Wastewater

? Acar, Y.B., Gale, R.J., Alshawabkeh, A.N., Marks, R.E., Puppala, S., Bricka, M. and Parker, R. (1995), Electrokinetic remediation: Basics and technology status. Journal of Hazardous Materials, 40 (2), 117-137.

Full Text: 1995\J Haz Mat40, 117.pdf

Abstract: Electrokinetic remediation, variably named as electrochemical soil processing, electromigration, electrokinetic decontamination or electroreclamation uses electric currents to extract radionuclides, heavy metals, certain organic compounds, or mixed inorganic species and some organic wastes from soils and slurries. An overview of the principals of the electrokinetic remediation technique in soils is presented. The types of waste and media in which the technology could potentially be applicable are outlined and some envisioned environmental uses of conduction phenomena in soils under electric fields are presented. The current status of the electrokinetic remediation technique and its limitations are discussed through a review of the bench-scale and pilot-scale tests. The recent findings of research on different techniques that may improve the technology’s effectiveness are mentioned and the status of ongoing efforts in wide-scale implementation and commercialization of the technique in the USA are described.

? Lin, J.S. and Hildemann, L.M. (1995), A nonsteady-state analytical model to predict gaseous emissions of volatile organic-compounds from landfills. Journal of Hazardous Materials, 40 (3), 271-295.

Full Text: 1995\J Haz Mat40, 271.pdf

Abstract: A general mathematical model is developed to predict emissions of volatile organic compounds (VOCs) from hazardous or sanitary landfills. The model is analytical in nature and includes important mechanisms occurring in unsaturated subsurface landfill environments: biogas flow, leachate flow, diffusion, adsorption, degradation, volatilization, and mass transfer limitations through the top cover. Two initial conditions simulating different environments are examined. The model is able to predict changes in subsurface concentrations and emission fluxes with time. The equations presented here can be extended to three dimensions to model VOC emissions from complex landfill sites.

Keywords: Adsorption, Air-Pollution, Behavior Assessment Model, Changes, Chemical-Transport, Degradation, Diffusion, Hazardous-Waste Landfills, Hydrophobic Pollutants, Landfill, Leachate, Limitations, Mass Transfer, Mathematical Model, Mechanisms, Model, Natural Sediments, Organic Compounds, Sanitary Landfills, Soil, Sorption, Trace Organics, Transfer, VOC, VOCs, Volatile Organic Compounds, Volatilization

Lindell, M.K. (1995), Assessing emergency preparedness in support of hazardous facility risk analyses: Application to siting a US hazardous-waste incinerator. Journal of Hazardous Materials, 40 (3), 297-319.

Full Text: J\J Haz Mat40, 297.pdf

Abstract: Increasing public resistance to hazardous materials transportation and facility operation has elicited a number of suggestions for improved risk communication, early community participation, and provision of incentives. Another potentially useful but hitherto neglected method of addressing local opposition to hazardous facility siting involves community emergency preparedness for a release of hazardous materials. This paper describes a procedure for analyzing local emergency preparedness in accordance with operational guidance from federal agencies in the United States and scientific principles derived from international research on disasters. This procedure identifies vulnerable areas of a community and assesses the capability of the community to take timely and effective protective actions including evacuation and sheltering in-place. Response capability is first assessed by verifying that local emergency response plans address the elements defined in state and federal guidance. Next, implementation analyses are conducted to determine whether the four critical functions of hazard detection and notification, protective action decision making, warning and public information, and protective action implementation can be accomplished with available resources under local conditions. These analyses indicate the degree to which formally designated emergency response activities of community agencies, as outlined by its Emergency Operations Plan (EOP), together with the informal social processes of emergency response known to operate in disasters, provide reasonable assurance of prompt and effective protective action by the public. Results of these analyses can provide administrative and judicial review processes with conclusions on the overall adequacy of local emergency preparedness, local emergency responders with suggestions as to which emergency preparedness improvements should be undertaken, and local residents with a better understanding of risk mitigation measures.

Keywords: Communication

? Miller, C.M. and Valentine, R.L. (1995), Oxidation behavior of aqueous contaminants in the presence of hydrogen-peroxide and filter media. Journal of Hazardous Materials, 41 (1), 105-116.

Full Text: 1995\J Haz Mat41, 105.pdf

Abstract: Hydrogen peroxide has been used as an oxidant to degrade contaminants in solutions and soils. A poor understanding of the numerous variables that are involved makes it difficult to determine dominant contaminant removal mechanisms. Our primary objective was to examine the relationship between contaminant (quinoline and nitrobenzene) degradation rate and the rate of hydrogen peroxide decomposition on filter media. Both batch and continuous flow column experiments were conducted. In general, the rate of contaminant degradation was proportional to the rate of hydrogen peroxide decomposition, but the mass of contaminant removed depended on the amount of hydrogen peroxide decomposed, filter medium concentration, and filter medium characteristics. For increasing filter medium concentration and equivalent loss of hydrogen peroxide, the mass of contaminant degraded was found to decrease. In addition, acid-hydroxylamine treatment of the selected filter medium, to examine the role of reducible metal oxide coatings, resulted in greater contaminant removals than the parent material despite a slower hydrogen peroxide decomposition rate. The observed hydrogen peroxide decomposition and contaminant oxidation results are consistent with a reaction scheme whose central elements include: (1) a rate limiting filter medium surface catalyzed reaction initiating hydrogen peroxide decomposition with the formation of a reactive intermediate, (2) a competing reaction of the intermediate with the filter medium surface, and (3) reaction of the same intermediate with the aqueous organic contaminant. Loss of quinoline and nitrobenzene is most likely a solution phase reaction because sorption of these compounds was small over the pH range 7-8 and oxidation efficiency did not increase with increasing filter medium concentration, which would be expected if the reactions were occurring on the surface. Finally, enhanced oxidation of quinoline and nitrobenzene on the treated material is explained by more efficient use of the reactive intermediates for contaminant oxidation due to a reduction in the number of scavenging sites associated with reducible metal oxide coatings.

Keywords: Batch, Column, Column Experiments, Contaminant, Contaminants, Degradation, Efficiency, Experiments, Fentons Reagent, Filter, Hydrogen Peroxide, Loss, Mechanisms, Media, Metal, Metal Oxide, Oxidation, Parent, pH, Quinoline, Reduction, Relationship, Removal, Soils, Sorption, Surface, Treatment, Understanding

? Gandhi, P., Erickson, L.E. and Fan, L.T. (1995), A simple method to study the effectiveness of bioremediation aided, pump-and-treat technology for aquifers contaminated by nonaqueous phase liquids. II. Multicomponent systems. Journal of Hazardous Materials, 41 (2-3), 185-204.

Full Text: 1995\J Haz Mat41, 185.pdf

Abstract: 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.

Keywords: Biodegradation, Bioremediation, Composition, Contaminants, Dissolution, Equilibria, Flushing, Fraction, Hydrogen-Peroxide, Inclusion, Kinetics, Mechanism, Microbes, Mixtures, Model, Multicomponent, Non-Aqueous Phase, Organic-Chemicals, Oxidation, Polycyclic Aromatic-Hydrocarbons, Removal, Simulation, Soil, Solubility, Sorption, Utilization, Water

? Narayanan, M., Davis, L.C., Tracy, J.C., Erickson, L.E. and Green, R.M. (1995), Experimental and Modeling Studies of the Fate of Organic Contaminants in the Presence of Alfalfa Plants. Journal of Hazardous Materials, 41 (2-3), 229-249.

Full Text: 1995\J Haz Mat41, 229.pdf

Abstract: 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 toluene 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.

Keywords: Adsorption, Bromide, Change, Contaminant, Contaminants, Dispersion, Effluent, Groundwater, Impact, Landfill, Modeling, Models, Phenol, Pollutants, Presence, Remediation, Soil, Soils, Toluene, Vegetation, Water

? Barnes, J.M., Apel, W.A. and Barrett, K.B. (1995), Removal of nitrogen-oxides from gas streams using biofiltration. Journal of Hazardous Materials, 41 (2-3), 315-326.

Full Text: 1995\J Haz Mat41, 315.pdf

Abstract: Nitrogen oxides (NOx) are primary air pollutants, and as such, there is considerable interest in the development of efficient, cost effective technologies to remediate NOx containing emissions, Biofiltration involves the venting of contaminated gas streams through biologically active material such as soil or compost. This technology has been used successfully to control odors as well as volatile organic compounds from a variety of industrial and public sources. The purpose of this study was to evaluate the feasibility of using biofiltration as a means to remediate NOx containing gas streams. Biofiltration studies measuring nitric oxide (NO) removal by bacteria indigenous to wood compost were conducted. Vertical biofilters (2l volume) constructed from glass process pipe (3 in i.d.xl2 in) were loaded with 1l of compost bed medium. Compaction of compost in the biofilters was minimized by the addition of wood chips (15% w/w). A nitrogen gas stream, containing various concentrations of NO (100-500 mu l/l), was purged (1 l/min) through the biofilter under single pass, continuous flow conditions. Adsorption studies comparing NO removal in autoclaved and non-autoclaved biofilters indicated that approximately 3% NO removal was attributed to abiotic uptake. Control of pH in the biofilter was a critical variable for maximum nitric oxide removal. Optimum denitrifying activity occurred at pH levels ranging between 6 and 7. Nitric oxide removal rates increased in biofilters treated with an external carbon and energy source. Biofilters treated with phosphate buffer containing either lactate or dextrose were capable of removing more than 90% of the NO from a 500 mu l/l NO gas stream flowing at 1 l/min.

Keywords: Adsorption, Air-Pollution, Bacteria, Biofilter, Biofiltration, Carbon, Compost, Control, Cost, Cost-Effective, Denitrifying Bacteria, Development, Feasibility, Gas, Indigenous, Nitric Oxide, Nitric-Oxide, Nitrogen, No, No Removal, NO_x, Organic Compounds, Oxides, pH, Phosphate, Pollutants, Process, Removal, Soil, Sources, Technology, Volatile Organic Compounds, Wood

? Groenewold, G.S., Ingram, J.C., Delmore, J.E., Appelhans, A.D. and Dahl, D.A. (1995), Rapid detection of tri-n-butyl phosphate on environmental surfaces using static sims. Journal of Hazardous Materials,