Personal Research Database

Full Text: 1998\J Haz Mat57, 209.pdf

Abstract: In situ air sparging is an effective method for removing volatile organic compounds from saturated soils and groundwater. Removal efficiency levels as high as 98% are often reported, and the remediation time is significantly less than that required for conventional pump and treat technology. However, predictions of the time required for contaminant mass removal by air sparging have been approximate at best due to a lack of understanding of the relative importance of the various mechanisms that are responsible for this contaminant removal. Volatilization is considered the most dominant mass transfer mechanism during the air sparging process. Dissolution, desorption and biodegradation are the other major mechanisms that determine the rate at which contaminants are partitioned into different phases or transformed into nonhazardous substances. Additionally, advection, dispersion and diffusion are the transport mechanisms that dictate the overall contaminant removal efficiency. This paper first describes these different mechanisms along with the factors that affect these mechanisms. Then, experimental data is presented for toluene removal from Ottawa sand and fine gravel by means of air sparging. The tests performed included batch tests to characterize the adsorption characteristics of toluene on the Ottawa sand, and air sparging column tests on both the sand and the gravel to provide information on the effects of soil type and injected air flow rate on the overall air sparging remedial efficiency. These test results are assessed in light of the mechanisms affecting contaminant removal during air sparging. (C) 1998 Elsevier Science B.V.

Keywords: Adsorption, Affect, Air Sparging, Batch, Biodegradation, Column, Contaminants, Desorption, Diffusion, Dissolution, Efficiency, Extraction, Factors, Groundwater, Groundwater Cleanup, Hydrocarbons, Hydrocarbons, In Situ, Information, Laboratory Investigation, Mass Transfer, Mechanism, Mechanisms, Natural Sediments, Organic Compounds, Organic-Compounds, Phase, Process, Remediation, Remediation, Removal, Removal Efficiency, Sand, Saturated Soils, Soil, Soils, Sorption, Technology, Test, Toluene, Transfer, Transport, Understanding, Volatile Organic Compounds

? Meng, X.G., Hua, Z., Dermatas, D., Wang, W. and Kuo, H.Y. (1998), Immobilization of mercury(II) in contaminated soil with used tire rubber. Journal of Hazardous Materials, 57 (1-3), 231-241.

Full Text: 1998\J Haz Mat57, 231.pdf

Abstract: The effectiveness of used tire rubber for immobilizing Hg(II) in a contaminated soil was evaluated using batch extraction and field rainwater leaching tests. The contaminated soil was prepared using a clay-loam spiked with mercury oxide or mercury chloride to yield a Hg(II) content of 300 mg/kg. When the contaminated soil was treated with 4% of tire rubber, Hg(II) concentration in an acetic acid leachate was reduced from 3500 ppb down to 34 ppb. Hg(II) concentration in the initial rainwater leachate was reduced from 84 ppb for untreated soil to 1.2 ppb for the rubber-treated soil. After 8 months of rainwater infiltration in the field. Hg(II) concentration decreased to less than 0.2 ppb for the treated soil. The rubber-treatment inhibited the evolution of metallic Hg-0 from the spiked soil samples possibly by retarding the reduction of Hg(II) to Hg-0 Batch extraction and adsorption results indicated that the rubber had high adsorption capacity for Hg(II) when pH values were between 2 and 8. (C) 1998 Elsevier Science B.V.

Keywords: Acetic Acid, Acid, Adsorption, Adsorption, Adsorption Capacity, Batch, Capacity, Contaminated Soil, Contamination, Effectiveness, Evolution, Extraction, Hg(II), Immobilization, Leachability, Leachate, Leaching, Leaching Tests, Mercury, Mercury(II), pH, Reduction, Rubber, Samples, Soil, Solidification, Stabilization, Stabilization, TCLP, Values

Gupta, G. and Torres, N. (1998), Use of fly ash in reducing toxicity of and heavy metals in wastewater effluent. Journal of Hazardous Materials, 57 (1-3), 243-248.

Full Text: J\J Haz Mat57, 243.pdf

Abstract: Fly ash is one of the most abundant waste materials; its major components make it a potential agent for the adsorption of heavy metal contaminants in water and wastewaters. The objective of this study was to measure the changes in toxicity of and heavy metals in a municipal (Salisbury, MD) wastewater treatment plant (SWTP) effluent on treatment with fly ash. The effluent from SWTP after treatment with fly ash for 4 h showed a significant reduction in toxicity, Cu and Pb, and PO₄^3-and NO₃^-contents. Toxicity of the effluent was measured using the marine luminescent microorganisms-Vibrio fischeri (‘Microtox’ test). Heavy metals (Cu, Pb and Zn) were measured using Atomic Absorption Spectrophotometry. Fly ash removed Cu and Pb from the effluent (through adsorption), and the removal of these toxic heavy metals resulted in the reduction of toxicity.

Keywords: Water, Adsorption, Area, Wastewater Treatment Plant, Effluent, Fly Ash, Toxicity, Heavy Metals

Yang, G.C.C. and Tsai, C.M. (1998), A study on heavy metal extractability and subsequent recovery by electrolysis for a municipal incinerator fly ash. Journal of Hazardous Materials, 58 (1-3), 103-120.

Full Text: J\J Haz Mat58, 103.pdf

Abstract: The extractability of heavy metals (Pb, Cd, Cr and Cu) from a municipal incinerator fly ash (designated MIFA S) using an acidic or basic extractant and their subsequent recovery by electrowinning using an electrolytic cell of the fluidized-bed type was investigated. The extractants studied were HCl, HNO₃, H₂SO₄, HOAc, NaOAc (pH = 8.15), and NaOAc (pH = 3) having 0.1 N in concentration. of which, NaOAc (pH = 3) outperformed the others and was selected for further studies. A 2(4-1) fractional factorial experimental design was adopted using liquid-to-solid (L/S) ratio, extractant concentration, extraction time, and initial pH as the experimental factors. The results show that L/S and extraction time played an important role in Pb extraction while L/S ratio and extractant concentration were important for Cr extraction. However, no controlling parameter was determined for Cd extraction, but a lower extraction efficiency was obtained if an initial pH of greater than 5 was used. For the study of electrolytic recovery, the experiments were carried out based on a 2(3-1) fractional factorial design using current density, initial pH, and operating temperature as the experimental factors. It was determined that current density was important to electrolytic recovery of Pb and Cu, but with an opposite effect. The other two experimental factors were insignificant, 96.70% of Pb and 93.69% of Cu were recovered from the leachate of MIFA S when 0.4 A-h of electrical charge was applied. The results obtained suggest that the recovery of heavy metals from MIFA S by solvent extraction and electrolytic recovery is technically feasible. (C) 1998 Elsevier Science B.V.

Keywords: Municipal Incinerator Fly Ash, Heavy Metal, Extraction, Recovery, Electrolysis, Fractional Factorial Design, Effect Analysis, Physicochemical Properties, Waste Combustion, Ion Solutions, Electrodeposition, Emissions, Behavior

Yang, G.C.C., Chou, S.W. and Hsu, T.F. (1998), Effects of chelant (EDTA) addition on properties of cement-solidified municipal incinerator fly ash. Journal of Hazardous Materials, 58 (1-3), 153-164.

Full Text: J\J Haz Mat58, 153.pdf

Abstract: A preliminary study was conducted to investigate the effects of EDTA (a chelant) addition on properties of cement-solidified municipal incinerator fly ash (MIFA) due to its increasing use for the removal of metals from soil and wastes. MIFA specimens (designated MIFA-A and MIFA-B, respectively) from two different municipal incineration plants were solidified by a cement-based technique. Properties studied included unconfined compressive strength (UCS) and leaching toxicity by Toxicity Characteristic Leaching Procedure (TCLP). Regardless of an addition of EDTA, experimental results have shown that UCS values of all the solidified MIFA specimens are greater than the R.O.C. EPA regulatory requirement for landfilling (i.e. 10 kg/cm²). The effect of EDTA addition on UCS was found to be trivial. Results of the Analysis of Variance (ANOVA) for UCS values also showed that the amount of EDTA added was not a controlling parameter in this work. It was found that solidification of MIFA by ordinary portland cement (OPC) alone is able to yield solidified monoliths of satisfactory properties. TCLP results of EDTA-added MIFA specimens also showed a limited effect due to EDTA addition. Whether an addition of other chelants would yield a significant effect on properties of solidified MIFA specimens needs further studies. (C) 1998 Elsevier Science B.V.

Keywords: Municipal Incinerator Fly Ash, Solidification, Chelant, Statistical Analysis, Physicochemical Properties, Waste Combustion

? Gau, S.H. and Chow, J.D. (1998), Landfill leachate characteristics and modeling of municipal solid wastes combined with incinerated residuals. Journal of Hazardous Materials, 58 (1-3), 249-259.

Full Text: 1998\J Haz Mat58, 249.pdf

Abstract: Sanitary landfilling of municipal solid wastes (MSW) combined with incinerated residuals is a disposal method specific to Taiwan, The purpose of this study was to explore the influences that adsorption, desorption, and biological reactions in landfilling may have on the quality of leachate. Not only did different combinations and the stratification of waste have to be considered, but anaerobic and semiaerobic landfilling have also been simulated. COD concentrations of leachate were processed by using a numerical method to get a simulation model for the estimation of variations in the organic pollutants in the leachate. The intensities of leachate from both semiaerobic and anaerobic landfilling, were also explored with this model, Comparing the simulation with the experimental data, we found that the degradation of the leachate quality was approximately similar for both type of data. (C) 1998 Elsevier Science B.V.

Keywords: Adsorption, Anaerobic, Co-Disposal, Cod, Degradation, Desorption, Disposal, Incinerated Residuals, Influences, Landfill, Landfill Leachate, Landfilling, Leachate, Leachate Model, Model, Modeling, MSW, Organic Pollutants, Pollutants, Quality, Semiaerobic Landfill, Simulation, Solid Wastes, Stratification, Taiwan, Variations

? Hsieh, T.L. and Kao, M.M. (1998), Adsorption of carbofuran on lateritic soils. Journal of Hazardous Materials, 58 (1-3), 275-284.

Full Text: 1998\J Haz Mat58, 275.pdf

Abstract: Adsorption of carbofuran on the four selected lateritic soils is studied using batch experiments. Accordingly, the key influencing factors of carbofuran adsorption are determined. The adsorption isotherms on the lateritic soils correspond well with the Freundlich isotherm. The adsorbed amounts of carbofuran in toluene-and-bromoform treated soils (i.e. organic matter has been partly removed) follow nearly the same pattern as those in the original soils, and the adsorbed amount increases with the increase in soil pH, organic matter acid clay contents. Also, the results show that the liming action and clay play important roles in carbofuran adsorption. The saturated adsorption maxima of carbofuran for the original soils are ca. 50% of the spiked amount. The distribution coefficient (K-d) increase with the increase in soil organic content and the solution/soil ratio. However, the low K-d obtained implies that carbofuran has a low affinity for the lateritic soil (i.e. more mobile). (C) 1998 Elsevier Science B.V.

Keywords: Acid, Adsorption, Adsorption Isotherms, Batch, Batch Experiments, Carbofuran, Clay, Distribution, Distribution Coefficient, Experiments, Factors, Freundlich, Freundlich Isotherm, Isotherm, Isotherms, Key, Lateritic Soil, Organic Matter, pH, Play, Roles, Soil, Soils, Sorption, Transport, Water

Yang, G.C.C. and Lin, S.L. (1998), Removal of lead from a silt loam soil by electrokinetic remediation. Journal of Hazardous Materials, 58 (1-3), 285-299.

Full Text: J\J Haz Mat58, 285.pdf

Abstract: In this study, a silt loam soil spiked with lead(ca. 1000 mg/kg) was treated by electrokinetics using an electric gradient of 1 V/cm. In all tests, 0.1 M acetic acid was used as the cathode reservoir fluid. However, anode reservoir fluids used were 0.1 M of acetic acid, citric acid, ethylenediaminetetraacetic acid (EDTA), respectively. Experimental results have shown that the electroosmotic (EO) flow in a direction towards the cathode would be reversed if the system pH is less than the point of zero charge (PZC) of the soil particles. Besides, the pH of both electrode reservoirs were found to be important to the removal of lead ions from soil. Experimental results have also shown that using acetic acid, citric acid, and EDTA as anode reservoir fluids resulted in lead removal efficiencies of 27.6%, 53.3%, and 11.2%, respectively. (C) 1998 Elsevier Science B.V.

Keywords: Contaminated Soil, Electrokinetic Remediation, Point of Zero Charge, Electroosmotic Flow, Electrode Reservoir Fluid, Contaminated Soil, Electroosmosis, Extraction, Kaolinite, Clay

? Sah, J.G. and Che, J.Y. (1998), Study of the electrokinetic process on Cd and Pb spiked soils. Journal of Hazardous Materials, 58 (1-3), 301-315.

Full Text: 1998\J Haz Mat58, 301.pdf

Abstract: This study examined three soil samples from different locations of Taiwan, According to those results, soil from Kaohsung County (KH) is weak basic clay loam with the highest cation exchange capacity (CEC) among all samples. Soil from a Cd contaminated paddy field in Kuanyin village, Taoyuan County (TY) is neutral loamy sand. And, Latosol soil from National Pingtung University of Science and Technology campus in Pingtung County (PT) is acidic clay. Tested samples without heavy metal spiked have low total (aqua regia digested) Cd contents; the natural Pb contents are all lower than 50 mg/kg. All samples can adsorb more Pb than Cd. The order of soils adsorption capacity on Cd and Pb is as follows: KH clay loam > TY loamy sand > PT clay. In addition, electrokinetic experiments were performed on Cd and Pb spiked and 0.1 M HCl saturated TY soil, indicating it to be the optimum Cd and Pb removal efficiency, PT soil is the second and KH soil is the worst. In contrast with all samples saturated in water, dilute HCl soaking facilitated the Cd and Pb removal during the electrokinetic process. The process did not influence Cd and Pb in the spiked KH soil. In water saturated spiked TY soil, Cd and Pb exist in highly stable forms in soil near cathode during the experiment. Acid soaking not only reduced the formation of the high Cd concentration suspension, but also assisted quite effectively in concentrating the Cd and Pb in the zone near cathode in stable residual and carbonate forms. Cd spiked and water saturated PT soil sample clearly demonstrated that Cd is concentrated in soil near the cathode after electrokinetic process. When soaking with 0.1 M HCl during the process, even better results were obtained. However, the exchangeable Cd in the soil near cathode is extremely high, thereby requiring further treatments. The Pb spiked water saturated PT soil displayed no change in Pb forms after the electrokinetic process. When soaked with 0.1 M HCl, the electrokinetic process yielded excellent results. In addition, spiked PT soil in 0.1 M HCl also has lower Cd and Pb stabilities during electrokinetic process. Moreover, elongating the process time may enhance the removal efficiency. (C) 1998 Elsevier Science B.V.

Keywords: Adsorption, Adsorption Capacity, Capacity, Carbonate, Cathode, Cation Exchange, Cation Exchange Capacity, Cd, Cd and Pb Spiked Soil, Cec, Change, Clay, Efficiency, Electrokinetic Process, Exchange, Experiments, HCl, Heavy Metal, Heavy-Metal, Influence, Metal, Natural, Pb, Process, Removal, Removal Efficiency, Samples, Sand, Soil, Soils, Taiwan, Water

? Valsaraj, K.T., Qaisi, K.M., Constant, W.D., Thibodeaux, L.J. and Ro, K.S. (1998), Diffusive transport of 2,4,6-trinitrotoluene (TNT) from contaminated soil to overlying water. Journal of Hazardous Materials, 59 (1), 1-12.

Full Text: 1998\J Haz Mat59, 1.pdf

Keywords: Adsorption, Contaminated Soil, Diffusion, Phytoremediation, Soil, TNT, Transport, Trinitrotoluene, Water

Wang, K.S., Chiang, K.Y., Perng, J.K. and Sun, C.J. (1998), The characteristics study on sintering of municipal solid waste incinerator ashes. Journal of Hazardous Materials, 59 (2-3), 201-210.

Full Text: J\J Haz Mat59, 201.pdf

Abstract: The study examines the sintering of incinerator ashes from municipal solid waste while considering the compact pressure, sintering temperature, and sintering time. Experimental results indicate that the compressive strength primarily influences the compact pressure used in forming the specimens. The specimens’ strengths increase at a sintering temperature ranging from 1120C to 1140C. However, the strength decreases with an increasing ignition loss of incinerator residues. As heavy metals are fixed and/or sealed in the sintered incinerator ashes, the process generates a ceramic-like solid having a sufficiently low metal teachability. The pH, Cd, and Cr concentrations of the leachate from the Toxicity Characteristic Leaching Procedure (TCLP) test are 0.10-0.70 mg/l, 0.05-0.30 mg/l, and 0.35-1.25 mg/l, respectively, all complying with the regulatory limits of Taiwan EPA. The above results point toward the feasibility of recycling the incinerator ashes as a construction material by sintering. (C) 1998 Elsevier Science B.V.

Keywords: Sintering Process, Municipal Solid Waste, Incinerator Ash, Leachates, Size

Singh, D.B., Rupainwar, D.C., Prasad, G. and Jayaprakas, K.C. (1998), Studies on the Cd(II) removal from water by adsorption. Journal of Hazardous Materials, 60 (1), 29-40.

Full Text: 1998\J Haz Mat60, 29.pdf

Abstract: The feasibility of using hematite for the removal of Cd(II) from aqueous solutions was investigated employing an adsorption technique. The adsorption was found to depend on Cd(II) concentration, pH, particle size of hematite, agitation rate and temperature of the system. The maximum removal was found to be 98% for the cadmium concentration of 44.88 µmol l^-1 at a temperature of 20C and pH 9.2 with 40 g l^-1 of hematite of particle size < 200 µm with agitation 125 rpm rate after 2 h. The applicability of the Langmuir isotherm was tested for the Cd(II)-hematite system at optimum conditions. The process follows first order kinetics. The mass transfer coefficient, diffusion coefficient and thermodynamic parameters have been determined to elucidate the mechanism of uptake. The uptake of cadmium is partially diffusion controlled and partially due to an electrostatic effect along with specific adsorption involving Cd⁺⁺ and CdOH⁺ which seem to play an effective role. The data has been subjected to multiple regression analysis and a computer model has been developed to predict the removal of Cd(II) from water under certain boundary conditions. The present technique has been found to be cost-effective. (C) 1998 Elsevier Science B.V.

Keywords: Adsorption, Hematite, Cadmium, Diffusion, Electrostatic Attraction, Multiple Regression Analysis, Fly-Ash, Cadmium(II)

? Ravikrishna, R., Valsaraj, K.T., Yost, S., Price, C.B. and Brannon, J.M. (1998), Air emissions from exposed, contaminated sediment and dredged materials 2. Diffusion from laboratory-spiked and aged field sediments. Journal of Hazardous Materials, 60 (1), 89-104.

Full Text: 1998\J Haz Mat60, 89.pdf

Abstract: The mass transfer of three polycyclic aromatic hydrocarbons (naphthalene, phenanthrene and pyrene) and a heterocyclic aromatic hydrocarbon (dibenzofuran) from sediment to air was studied in a large-area flux chamber. A laboratory-spiked local (University Lake, UL) sediment and an aged contaminated field (Indiana Harbor Canal, IHC) sediment was used. The effects of initial sediment moisture content, and changing air relative humidity were investigated. For high moisture conditions in the UL sediment, the flux remained large whereas for low moisture conditions, there was a sharp decrease in flux as a result of surface drying of the sediment. Under similar air velocities and moisture conditions, the flux from the aged MC sediment was considerably smaller than from the laboratory-spiked UL sediment. Whereas, the flux from laboratory-spiked UL sediment was predicted satisfactorily by a conceptual mathematical model, that from the aged IHC sediment did not agree with the model predictions. It was concluded that only a portion of the contaminant was available for desorption from the aged sediment due to the differences in the sorption characteristics of relatively fresh and aged contaminated sediments. (C) 1998 Elsevier Science B.V.

Keywords: Adsorption, Aged, Air Emissions, Desorption, Diffusion, Humidity, Hydrocarbons, Mass Transfer, Mathematical Model, Model, Naphthalene, Phenanthrene, Polycyclic Aromatic Hydrocarbons, Pyrene, Sediment, Sediments, Soil Gas Transport, Soils, Sorption, Surface, Transfer, Vapors

? Abumaizar, R.J., Kocher, W. and Smith, E.H. (1998), Biofiltration of BTEX contaminated air streams using compost-activated carbon filter media. Journal of Hazardous Materials, 60 (2), 111-126.

Full Text: 1998\J Haz Mat60, 111.pdf

Abstract: Three laboratory-scale biofilter columns were operated for 82 days to investigate the removal of benzene, toluene, ethylbenzene, and a-xylene (BTEX) from a waste gas stream. The columns contain a mixture of yard waste and sludge compost as the base biofilter material. Different amounts of granular activated carbon (GAC) are mixed with the compost in two of the three columns to evaluate the extent to which biofilter performance can be enhanced. The columns displayed preferential utilization of benzene followed by toluene, ethylbenzene, and o-xylene, respectively. Removal efficiencies of greater than or equal to 90% were achieved for inlet concentrations of greater than or equal to 200 ppm of each of the BTEX compounds and a gas loading rate of 17.6 m(3)/m(2) h in all columns over the period of study. During sudden increases in the gas flow rate or the BTEX influent concentration, biofilters containing GAC exhibited significantly higher removal efficiencies and more stable operation than the biofilter containing only compost. (C) 1998 Elsevier Science B.V. All rights reserved.

Keywords: Achieved, Activated Carbon, Adsorption, Air Pollution, Base, Benzene, Biodegradation, Biofilm, Biofilter, Biofiltration, BTEX, Carbon, Compost, Ethylbenzene, GAC, Granular Activated Carbon, Media, Mixed, Organic Compounds, Performance, Removal, Rights, Sludge, Toluene, Utilization

? Aminabhavi, T.M. and Naik, H.G. (1998), Chemical compatibility study of geomembranes - sorption/desorption, diffusion and swelling phenomena. Journal of Hazardous Materials, 60 (2), 175-203.

Full Text: 1998\J Haz Mat60, 175.pdf

Abstract: Sorption/desorption results of n-alkanes into high density polyethylene, Linear low density polyethylene, very low density polyethylene and polypropylene geomembranes are presented at 25, 50 and 70 C. Sorption results are obtained by a gravimetric method and diffusion coefficients have been calculated by using Fick’s equation from the initial linear portions of the sorption/desorption curves. Swelling of the geomembranes was studied from a measurement of the increase in volume, thickness and diameter. From a temperature dependence of sorption and diffusion coefficients, the Arrhenius parameters have been calculated. Liquid-concentration profiles have been computed using Fick’s equation for the appropriate initial and boundary conditions. The results of this study may have relevance in selecting the suitable geomembrane for a specific application in hazardous waste chemical ponds and other similar situations. (C) 1998 Elsevier Science B.V. All rights reserved.

Keywords: Alkanes, Dependence, Diffusion, Diffusion Coefficients, Esters, Geomembrane, Hazardous Waste, Isotactic Polypropylene, Ketones, Laboratory Experiment, Measurement, Molecular-Transport, N-Alkanes, Organic Liquids, Polymer Membranes, Propylene Random Copolymer, Relevance, Rights, Sorption, Sorption, Sorption, Desorption, Swelling, Temperature

Simonič, M. and Ozim, V. (1998), Thermal water treatment with granular activated carbon. Journal of Hazardous Materials,