hurtado, C.; Cañameras, N.; Domínguez, C.; Price, G.W.; Comas, J.; Bayona, J. Journal of hazardous materials Vol. 323, num. Part A, p. 386-393 DOI: 10.1016/j.jhazmat.2016.04.046 Data de publicació: 2017-02-05 Article en revista
Although crop uptake of emerging organic contaminants (EOC) from irrigation water and soils has been previously reported, successful mitigation strategies have not yet been established. In this study, soil was amended with a wood-based biochar (BC) at two rates (0, 2.5 and 5% w/w) to evaluate the effect on mitigation of EOC uptake (i.e. bisphenol A, caffeine, carbamazepine, clofibric acid, furosemide, ibuprofen, methyl dihydrojasmonate, tris(2-chloroethyl)phosphate, triclosan, and tonalide) in lettuce (Lactuca sativa L.). After 28 days of irrigation with water containing EOCs at 15 µg L-1, the average EOC concentration in roots and leaves decreased by 20–76% in biochar amended soil relative to non BC-amended soil. In addition, the enantiomeric fractions (EF) of ibuprofen (IBU) in biochar amended soils (EF = 0.58) and unamended soils (EF = 0.76) suggest that the IBU sorbed fraction in BC is more recalcitrant to its biodegradation.
Hurtado, C.; Perez-Babace, L.; Cañameras, N.; Comas, J.; Bayona, J.; Dominguez, C. Journal of hazardous materials Vol. 305, p. 139-148 DOI: 10.1016/j.jhazmat.2015.11.039 Data de publicació: 2016-02-15 Article en revista
The widespread distribution of emerging organic contaminants (EOCs) in the water cycle can lead to their incorporation in irrigated crops, posing a potential risk for human consumption. To gain further insight into the processes controlling the uptake of organic microcontaminants, Batavia lettuce (Lactuca sativa) grown under controlled conditions was watered with EOCs (e.g., non-steroidal anti-inflammatories, sulfonamides, ß—blockers, phenolic estrogens, anticonvulsants, stimulants, polycyclic musks, biocides) at different concentrations (0–40 µg L-1). Linear correlations were obtained between the EOC concentrations in the roots and leaves and the watering concentrations for most of the contaminants investigated. However, large differences were found in the root concentration factors (RCFi = 0.27–733) and leaf translocation concentration factors (LTCFi = 0–3) depending on the persistence of the target contaminants in the rhizosphere and the specific physicochemical properties of each one. With the obtained dataset, a simple predictive model based on a linear regression and the root bioconcentration and translocation factors can be used to estimate the concentration of the target EOCs in leaves based on the dose supplied in the irrigation water or the soil concentration. Finally, enantiomeric fractionation of racemic ibuprofen from the initial spiking mixture suggests that biodegradation mainly occurs in the rhizosphere.
Aerated batch reactors (2.5 L) fed either with urban or synthetic wastewater were inoculated with microalgae (dominated by Chlorella sp. and Scenedesmus sp.) to remove caffeine, ibuprofen, galaxolide, tributyl phosphate, 4-octylphenol, tris(2-chloroethyl) phosphate and carbamazepine for 10 incubation days. Non-aerated and darkness reactors were used as controls. Microalgae grew at a rate of 0.25 d-1 with the complete removal of N-NH4 during the course of the experiment. After 10 incubation days, up to 99% of the microcontaminants with a Henry’s law constant higher than 3 10-1 Pa m3 mol-1 (i.e., 4-octylphenol, galaxolide, and tributyl phosphate) were removed by volatilization due to the effect of air stripping. Whereas biodegradation was effective for removing ibuprofen and caffeine, carbamazepine and tris(2-chloroethyl) phosphate behaved as recalcitrant compounds. The use of microalgae was proved to be relevant for increasing the biodegradation removal efficiency of ibuprofen by 40% and reducing the lag phase of caffeine by 3 days. Moreover, the enantioselective biodegradation of S-ibuprofen suggested a biotic prevalent removal process, which was supported by the identification of carboxy-ibuprofen and hydroxy-ibuprofen. The results from microalgae reactors fed with synthetic wastewater showed no clear evidences of microalgae uptake of any of the studied microcontaminants.
Athalathil, S.; Erjavec, B.; Kaplan, R.; Stüber, F.; Bengoa, C.; Font, J.; Fortuny, A.; Pintar, A.; Fabregat, A. Journal of hazardous materials Vol. 300, p. 406-414 DOI: 10.1016/j.jhazmat.2015.07.025 Data de publicació: 2015-12-30 Article en revista
The enhanced oxidative potential of sludge carbon/TiO2 nano composites (SNCs), applied as heterogeneous catalysts in advanced oxidation processes (AOPs), was studied. Fabrification of efficient SNCs using different methods and successful evaluation of their catalytic oxidative activity is reported for the first time. Surface modification processes of hydrothermal deposition, chemical treatment and sol-gel solution resulted in improved catalytic activity and good surface chemistry of the SNCs. The solids obtained after chemical treatment and hydrothermal deposition processes exhibit excellent crystallinity and photocatalytic activity. The highest photocatalytic rate was obtained for the material prepared using hydrothermal deposition technique, compared to other nanocomposites. Further, improved removal of bisphenol A (BPA) from aqueous phase by means of catalytic ozonation and catalytic wet air oxidation processes is achieved over the solid synthesized using chemical treatment method. The present results demonstrate that the addition of TiO2 on the surface of sludge carbon (SC) increases catalytic oxidative activity of SNCs. The latter produced from harmful sludge materials can be therefore used as cost-effective and efficient sludge derived catalysts for the removal of hazardous pollutants. (C) 2015 Elsevier B.V. All rights reserved.
Ramírez-Camacho, J. G.; Pastor, E.; Casal, J.; Amaya, R.; Muñoz Giraldo, Felipe Journal of hazardous materials Vol. 298, p. 210-220 DOI: 10.1016/j.jhazmat.2015.05.033 Data de publicació: 2015-11-15 Article en revista
Parallel pipelines are frequently installed over long distances, due to the difficulty in creating or maintaining the required corridor. This implies that a release in one pipeline can seriously affect another one. The main risks associated with this domino effect are erosion by fluid-sand jets and the thermal action of jet fires. In this paper a survey has been performed on the accidents that have occurred, and the diverse associated domino sequences are analyzed. The probability of occurrence of domino effect is a function of the location of the hole, the jet direction and solid angle, the diameter of both pipelines and the distance between them. A mathematical model has been developed to estimate this probability. The model shows how the probability of domino effect decreases with the distance and diameter of the source pipe, and increases with the diameter of the target pipe. Its frequency can be estimated from this probability and from the frequency of the initiating pipe failure plus, in the case of jet fire impingement, the probability of ignition. The frequency of the target pipe failure thus calculated, always higher than its individual frequency, allows a more realistic risk analysis. (C) 2015 Elsevier B.V. All rights reserved.
Matamoros Mercadal, Víctor; Gutierrez, R.; Ferrer, I.; Garcia, J.; Bayona, J. Journal of hazardous materials Vol. 288, p. 34-42 DOI: 10.1016/j.jhazmat.2015.02.002 Data de publicació: 2015-05-15 Article en revista
The effect of hydraulic retention time (HRT) and seasonality on the removal efficiency of 26 organic microcontaminants from urban wastewater was studied in two pilot high-rate algal ponds (HRAPs). The targeted compounds included pharmaceuticals and personal care products, fire retardants, surfactants, anticorrosive agents, pesticides and plasticizers, among others. The pilot plant, which was fed at a surface loading rate of 7-29 g of COD m(-2) d(-1), consisted of a homogenisation tank and two parallel lines, each one with a primary settler and an HRAP with a surface area of 1.5 m(2) and a volume of 0.5 m(3). The two HRAPs were operated with different HRTs (4 and 8 d). The removal efficiency ranged from negligible removal to more than 90% depending on the compound. Microcontaminant removal efficiencies were enhanced during the warm season, while the HRT effect on microcontaminant removal was only noticeable in the cold season. Our results suggest that biodegradation and photodegradation are the most important removal pathways, whereas volatilization and sorption were solely achieved for hydrophobic compounds (log Row >4) with a moderately high Henry's law constant values (11-12 Pa m(-3) mol(-1)) such as musk fragrances. Whereas acetaminophen, ibuprofen and oxybenzone presented ecotoxicological hazard quotients (HQs) higher than 1 in the influent wastewater samples, the HQs for the effluent water samples were always below 1. (C) 2015 Elsevier B.V. All rights reserved.
Montebello, A.M.; Mora, M.; Lopez, L.; Bezerra , T.; Gamisans, X.; Lafuente Sancho, Francisco Javier; Baeza, M.; Gabriel, D. Journal of hazardous materials Vol. 280, p. 200-208 DOI: 10.1016/j.jhazmat.2014.07.075 Data de publicació: 2014-09-15 Article en revista
Nearly 1.0×108 tonnes of phosphogypsum were accumulated during last 50 years on a 1200ha disposal site near Huelva town (SW of Spain). Previous measurements of exhalation rates offered very variable values, in such a way that a worst case scenario could not be established. Here, new experimental data coupled to numerical simulations show that increasing the moisture contents or the temperature reduces the exhalation rate whilst increasing the radon potential or porosity has the contrary effect. Once the relative effects are compared, it can be drawn that the most relevant parameters controlling the exhalation rate are radon potential (product of emanation factor by 226Ra concentration) and moisture saturation of PG. From wastes management point of view, it can be concluded that piling up the waste increasing the height instead of the surface allows the reduction of the exhalation rate. Furthermore, a proposed cover here is expected to allow exhalation rates reductions up to 95%. We established that the worst case scenario corresponds to a situation of extremely dry winter. Under these conditions, the radon exhalation rate (0.508Bqm-2s-1) would be below though close to the upper limit established by U.S.E.P.A. for inactive phopsphogypsum piles (0.722Bqm-2s-1).
Jurado, A.; Gago, P.; Vázquez, E.; Carrera, J.; Pujades, E.; Díaz-Cruz, S.; Barceló, D. Journal of hazardous materials Vol. 271, p. 141-149 DOI: 10.1016/j.jhazmat.2014.01.036 Data de publicació: 2014-04-30 Article en revista
The occurrence and fate of UV filters (UV F) in an urban aquifer in correlation with (1) the spatial distribution of UV Fin Barcelona's groundwater, (2) the depth of the groundwater sample, (3) the physicochemical properties of the target compounds, (4) the recharge sources, and (5) the redox conditions of the Barcelona aquifers, were studied for the first time. The highest groundwater concentrations and the largest number of detected UV F were observed in an aquifer recharged by a polluted river (around 55 ng/L in SAP-4). In contrast, the urbanized areas had lower concentrations (around 20 ng/L in MPSP-1). Two pathways can be identified for UV F to enter the aquifers: (1) leakage of row sewage from the sewage network in urbanized areas and (2) wastewater treatment plant (WWTP) effluents discharged into the river. Measured concentrations of UV F were significantly much lower than those estimated from the waste water proportion in groundwater samples suggesting that UV F might undergo transformation processes in both reducing and oxidizing conditions. (c) 2014 Elsevier B.V. All rights reserved.
Athalathil, S.; Stüber, F.; Bengoa, C.; Font, J.; Fortuny, A.; Fabregat, A. Journal of hazardous materials Vol. 267, p. 21-30 DOI: 10.1016/j.jhazmat.2013.12.031 Data de publicació: 2014-02-28 Article en revista
This work presents the preliminary study of new carbonaceous materials (CMs) obtained from exhausted sludge, their use in the heterogeneous anaerobic process of biodecolorization of azo dyes and the comparison of their performance with one commercial active carbon. The preparation of carbonaceous materials was conducted through chemical activation and carbonization. Chemical activation was carried out through impregnation of sludge-exhausted materials with ZnCl2 and the activation by means of carbonization at different temperatures (400, 600 and 800 degrees C). Their physicochemical and surface characteristics were also investigated. Sludge based carbonaceous (SBC) materials SBC400, SBC600 and SBC800 present values of 13.0, 1113 and 202.0 m(2)/g of surface area. Biodecolorization levels of 76% were achieved for SBC600 and 86% for SBC800 at space time (tau) of 1.0 min, similar to that obtained with commercial activated carbons in the continuous anaerobic up-flow packed bed reactor (UPBR). The experimental data fit well to the first order kinetic model and equilibrium data are well represented by the Langmuir isotherm model. Carbonaceous materials show high level of biodecolorization even at very short space times. Results indicate that carbonaceous materials prepared from sludge-exhausted materials have outstanding textural properties and significant degradation capacity for treating textile effluents. (C) 2013 Elsevier B.V. All rights reserved.
del Valle-Zermeño, R.; Formosa, J.; Prieto, M.; Nadal, R.; Niubó, M.; Chimenos, J. M. Journal of hazardous materials Vol. 266, p. 132-140 DOI: 10.1016/j.jhazmat.2013.12.020 Data de publicació: 2014-02-15 Article en revista
A granular material (GM) to be used as road sub-base was formulated using 80% of weathered bottom ash (WBA) and 20% of mortar. The mortar was prepared separately and consisted in 50% APC and 50% of Portland cement. A pilot-scale study was carried on by constructing three roads in order to environmentally evaluate the performance of GM in a real scenario. By comparing the field results with those of the column experiments, the overestimations observed at laboratory scale can be explained by the potential mechanisms in which water enters into the road body and the pH of the media. An exception was observed in the case of Cu, whose concentration release at the test road was higher. The long-time of exposure at atmospheric conditions might have favoured oxidation of organic matter and therefore the leaching of this element. The results obtained showed that immobilization of all heavy metals and metalloids from APC is achieved by the pozzolanic effect of the cement mortar. This is, to the knowledge of the authors, the only pilot scale study that is considering reutilization of APC as a safe way to disposal. (C) 2013 Elsevier B.V. All rights reserved.
A granular material (GM) to be used as road sub-base was formulated using 80% of weathered bottom ash (WBA) and 20% of mortar. The mortar was prepared separately and consisted in 50% APC and 50% of Portland cement. A pilot-scale study was carried on by constructing three roads in order to environmentally evaluate the performance of GM in a real scenario. By comparing the field results with those of the column experiments, the overestimations observed at laboratory scale can be explained by the potential mechanisms in which water enters into the road body and the pH of the media. An exception was observed in the case of Cu, whose concentration release at the test road was higher. The long-time of exposure at atmospheric conditions might have favoured oxidation of organic matter and therefore the leaching of this element. The results obtained showed that immobilization of all heavy metals and metalloids from APC is achieved by the pozzolanic effect of the cement mortar. This is, to the knowledge of the authors, the only pilot scale study that is considering reutilization of APC as a safe way to disposal.
The objective of this article is to develop and apply several simple and rough indicators for river aquatic ecosystems assessment in order to screen potential chemical stressors. Several indicators, based on toxicity (PNEC) and on legislation levels (EQS) have been developed. All these indicators are ratios that were calculated by using public and private data of concentrations of a large list of compounds during a period of five years, including metals and organic compounds in the lower part of the Llobregat river basin at the intake of the drinking water treatment plant. Additionally, new campaigns were executed for increasing the information available on the presence of compounds not routinely analyzed, such as some other pesticides and pharmaceuticals. In the case of inorganic pollutants, the indicators obtained in this river section showed significant risk especially for zinc, but also for copper, nickel and barium. For organic pollutants, the pesticides terbuthylazine, diazinon, 2-methyl-4-chlorophenoxyacetic (MCPA), and in a few cases, chlorpyrifos and lindane, also showed indexes above the threshold. Among the pharmaceuticals, the antibiotics clarithromycin and ciprofloxacin were the only ones with risk indicators adverse to ecosystems. The specific values of the indexes obtained rely on the quantity and quality of the data available, so their interpretation should take into account that some values can be high due to the use of too conservative toxicological information.
The objective of this article is to develop and apply several simple and rough indicators for river aquatic ecosystems assessment in order to screen potential chemical stressors. Several indicators, based on toxicity (PNEC) and on legislation levels (EQS) have been developed. All these indicators are ratios that were calculated by using public and private data of concentrations of a large list of compounds during a period of five years, including metals and organic compounds in the lower part of the Llobregat river basin at the intake of the drinking water treatment plant. Additionally, new campaigns were executed for increasing the information available on the presence of compounds not routinely analyzed, such as some other pesticides and pharmaceuticals. In the case of inorganic pollutants, the indicators obtained in this river section showed significant risk especially for zinc, but also for copper, nickel and barium. For organic pollutants, the pesticides terbuthylazine, diazinon, 2-methyl-4-chlorophenoxyacetic (MCPA), and in a few cases, chlorpyrifos and lindane, also showed indexes above the threshold. Among the pharmaceuticals, the antibiotics clarithromycin and ciprofloxacin were the only ones with risk indicators adverse to ecosystems. The specific values of the indexes obtained rely on the quantity and quality of the data available, so their interpretation should take into account that some values can be high due to the use of too conservative toxicological information
Kumar, V.; De Barros, F.P.J.; Schuhmacher, M.; Fernandez, D.; Sanchez-Vila, X. Journal of hazardous materials Vol. 263, num. 1, p. 197-206 DOI: 10.1016/j.jhazmat.2013.08.036 Data de publicació: 2013-12 Article en revista
Biobarriers, as permeable reactive barriers (PRBs), are a common technology that mainly uses bacteria to remediate groundwater in polluted aquifers. In this study, we propose to use Trametes versicolor, a white-rot fungus, as the reactive element because of its capacity to degrade a wide variety of highly recalcitrant and xenobiotic compounds. A laboratory-scale artificial aquifer was constructed to simulate groundwater flow under real conditions in shallow aquifers. Orange G dye was chosen as a contaminant to visually monitor the hydrodynamic behaviour of the system and any degradation of the dye by the fungus. Batch experiments at different pH values (6 and 7) and several temperatures (15 °C, 18 °C, 20 °C and 25 °C) were performed to select the appropriate residence time and glucose consumption rate required for continuous treatment. The maximum Orange G degradation was 97%. Continuous degradation over 85% was achieved for more than 8 days. Experimental results indicate for the first time that this fungus can potentially be used as a permeable reactive barrier in real aquifers.
The growing importance of liquefied natural gas (LNG) to global energy demand has increased interest in the possible hazards associated with its storage and transportation. Concerning the event of an LNG spill, a study was performed on the relationship between the distance at which the lower flammability limit (LFL) concentration occurs and that corresponding to the visible contour of LNG vapor clouds. A parameter called the dispersion safety factor (DSF) has been defined as the ratio between these two lengths, and two expressions are proposed to estimate it. During an emergency, the DSF can be a helpful parameter to indicate the danger of cloud ignition and flash fire.
The growing importance of liquefied natural gas (LNG) to global energy demand has increased interest
in the possible hazards associated with its storage and transportation. Concerning the event of an LNG
spill, a study was performed on the relationship between the distance at which the lower flammability
limit (LFL) concentration occurs and that corresponding to the visible contour of LNG vapor clouds. A
parameter called the dispersion safety factor (DSF) has been defined as the ratio between these two
lengths, and two expressions are proposed to estimate it. During an emergency, the DSF can be a helpful
parameter to indicate the danger of cloud ignition and flash fire
The occurrence of 166 emerging compounds and four heavy metals (Cd, Ni, Hg and Pb) in treated wastewater and groundwater has been monitored at the Llobregat delta (Barcelona, Spain) over a period of 3 years. Selected compounds were pharmaceuticals, personal care products (PCPs), dioxins, polycyclic aromatic hydrocarbons (PAHs) and priority substances included in the 2008/105/CE Directive. Analysis was performed in tertiary treated wastewater (TWW), after an additional treatment of ultrafiltration reverse osmosis and UV disinfection, and groundwater from a deep confined aquifer. This aquifer is artificially recharged with TWW through injection wells. After the advanced treatment, 38 pharmaceuticals, 9 PCPs, 9 pesticides and 7 PAHs still showed a frequency of detection higher than 25% in the TWW, although at low concentration levels (ng/l). Not all active compounds found in the TWW were present in groundwater, indicating possible degradation within the aquifer media after the injection. A number of chemicals, mainly 10 pesticides and 10 pharmaceuticals were only present in groundwater samples, confirming a different origin than the injected TWW, probably agricultural activities and/or infiltration of poorly treated wastewater.
Sanchez, I.; Stüber, F.; Fabregat, A.; Font, J.; Fortuny, A.; Bengoa, C. Journal of hazardous materials Vol. 199-200, p. 328-335 DOI: 10.1016/j.jhazmat.2011.11.024 Data de publicació: 2012-01-15 Article en revista
The convection heat transfer phenomenon in vertical jet fires was experimentally analyzed. In these experiments, turbulent propane flames were generated in subsonic as well as sonic regimes. The experimental data demonstrated that the rate of convection heat transfer increases by increasing the length of the flame. Assuming the solid flame model, the convection heat transfer coefficient was calculated. Two equations in terms of adimensional numbers were developed. It was found out that the Nusselt number attains greater values for higher values of the Rayleigh and Reynolds numbers. On the other hand, the Froude number was analyzed only for the subsonic flames where the Nusselt number grows by this number and the diameter of the orifice.
Gibert, O.; Rötting, T.; Cortina, J.; De Pablo, J.; Carrera, J.; Ayora, C.; Bolzicco, J. Journal of hazardous materials Vol. 191, num. 1-3, p. 287-295 DOI: 10.1016/j.jhazmat.2011.04.082 Data de publicació: 2011-07-15 Article en revista
MSWI bottom ash is a well-graded highly compactable material that can be used as a road material in unbound pavements. Achieving the compactness assumed in the design of the pavement is of primary
concern to ensure long term structural stability. Regulations on road construction in a number of EU countries rely on standard tests originally developed for natural aggregates, which may not be appropriate
to accurately assess MSWI bottom ash. This study is intended to assist in consistently assessing MSWI bottom ash compaction by means of the Proctor method. This test is routinely applied to address unbound road materials and suggests two methods. Compaction parameters show a marked procedural dependency due to the particle morphology and weak particle strength of ash. Re-compacting a single batch sample to determine Proctor curves is a common practise that turns out to overvalue optimum
moisture contents and maximum dry densities. This could result in wet-side compactions not meeting stiffness requirements. Inaccurate moisture content measurements during testing may also induce erroneous
determinations of compaction parameters. The role of a number of physical properties of MSWI bottom ash in compaction is also investigated.
Herein is presented a study on the long-term leaching behaviour of nickel containing wastes stabilized/solidified with magnesium potassium phosphate cements. Two different semi-dynamic leaching tests were carried out on monolithic materials: ANS16.1 test with liquid-to-solid ratio (L/S) of 10dm3 kg−1
and increasing renewal times, and ASTM C1308 test with liquid-to-solid ratio (L/S) of 100dm3 kg−1 and constant renewal time of 1 day. ASTM C1308 provides a lower degree of saturation of the leachant with respect to the leached material. The effectiveness of magnesium potassium phosphate cements for the
inertization of nickel was proved. XRD analyses showed the presence of bobierrite on the monolith’s surface after the leaching test, which had not been detected prior to the leaching test. In addition, the calculated cumulative release of the main components of the stabilization matrix (Mg2+, total P and K+)was represented versus time in logarithmic scale and it was determined if the leaching mechanism corresponds to diffusion. Potassium is released by diffusion, while total phosphorous and magnesium show dissolution. Magnesium release in ANS 16.1 is slowed down because of saturation of the leachant. Experimental results demonstrate the importance of L/S ratio and renewal times in semi-dynamic leaching tests.
Kiliç, E.; Font Vallès, Joaquim; Puig, R.; Colak, S.; Celik, D. Journal of hazardous materials Vol. 185, num. 1, p. 456-462 DOI: 10.1016/j.jhazmat.2010.09.054 Data de publicació: 2011-01-15 Article en revista
Kiliç, E.; Puig, R.; Baquero, G.; Font Vallès, Joaquim; Colak, S.; Gürler, D. Journal of hazardous materials Vol. 192, num. 1, p. 393-401 DOI: 10.1016/j.jhazmat.2011.05.040 Data de publicació: 2011 Article en revista
Life cycle assessment (LCA) was used to evaluate the environmental impact of an oxidative chromium recovery method from tannery sludge, in comparison with the usual landfilling process. Three improvement
options (water reduction, byproduct use and anaerobic sludge digestion) were considered. The results showed that the proposed chromium recovery process would be better environmentally than conventional landfilling in all the evaluated impact categories if the amount of chromium recovered was 43 kg per ton of sludge. This amount could be recovered if the chromium concentration was about 20 times higher than that considered in this study. Alternatively, a lower chromium concentration would produce a better result if the recovery method was optimized and implemented at industrial rather
than laboratory scale, and if more accurate data were provided on environmental credits for avoiding the chromium production process. Thus, the recovery method is environmentally beneficial when tannery
sludge contains a chromium concentration of about 100,000 ppm. According to the literature, such concentrations are not unusual. The results could serve as the basis for further environmental improvements
in chromium recovery and tannery sludge management and should be used in decision-making processes, especially for end-of-pipe treatments.
Oliva, J.; De Pablo, J.; Cortina, J.; Cama, J.; Ayora, C. Journal of hazardous materials Vol. 184, num. 1-3, p. 364-374 DOI: 10.1016/j.jhazmat.2010.08.045 Data de publicació: 2010-12-15 Article en revista
Carrère, H.; Dumas, C.; Battimelli, A.; Batstone, D.; Delgenès, J.; Steyer, J.; Ferrer, I. Journal of hazardous materials Vol. 183, num. 1-3, p. 1-15 DOI: 10.1016/j.jhazmat.2010.06.129 Data de publicació: 2010-11 Article en revista
Sureda, R.; Rovira, M.; De Pablo, J.; Casas, I.; Gimenez, F.; Martinez, X. Journal of hazardous materials Vol. 181, num. 13, p. 881-885 DOI: 10.1016/j.jhazmat.2010.05.095 Data de publicació: 2010-09-15 Article en revista
Strontium-90 is considered the most important radioactive isotope in the environment and one of the most frequently occurring radionuclides in groundwaters at nuclear facilities. The uranyl peroxide studtite (UO2O2 center dot 4H(2)O) has been observed to be formed in spent nuclear fuel leaching experiments and seems to have a relatively high sorption capacity for some radionuclides. In this work, the sorption of strontium onto studtite is studied as a function of time. strontium concentration in solution and pH. The main results obtained are (a) sorption is relatively fast although slower than for cesium; (b) strontium seems to be sorbed via a monolayer coverage of the studtite surface, (c) sorption has a strong dependence on ionic strength, is negligible at acidic pH, and increases at neutral to alkaline pH (almost 100% of the strontium in solution is sorbed above pH 10). These results point to uranium secondary solid phase formation on the spent nuclear fuel as an important mechanism for strontium retention in a high-level nuclear waste repository (HLNW). (C) 2010 Elsevier B.V. All rights reserved.
The main features of domino accidents in process/storage plants and in the transportation of hazardous
materials were studied through an analysis of 225 accidents involving this effect. Data on these accidents,
which occurred after 1961, were taken from several sources. Aspects analyzed included the accident
scenario, the type of accident, the materials involved, the causes and consequences and the most common
accident sequences. The analysis showed that the most frequent causes are external events (31%) and
mechanical failure (29%). Storage areas (35%) and process plants (28%) are by far the most common
settings for domino accidents. Eighty-nine per cent of the accidents involved flammable materials, the
most frequent of which was LPG. The domino effect sequences were analyzed using relative probability
event trees. The most frequent sequences were explosion→fire (27.6%), fire→explosion (27.5%) and
Leopold, A.A.; Coll, M.T.; Fortuny, A.; Rathore, N.; Sastre, A. Journal of hazardous materials Vol. 182, num. 1-3, p. 903-911 DOI: 10.1016/j.jhazmat.2010.07.004 Data de publicació: 2010-07-29 Article en revista
This paper describes experimental work and the mathematical modeling of solvent extraction of cadmium(
II) from neutral and acidic aqueous chloride media with a Cyanex 923 extractant in Exxol D-100.
Solvent extraction experiments were carried out to analyze the influence of variations in the composition
of the aqueous and organic phases on the efficiency of cadmium(II) extraction. In neutral and acidic
chloride conditions, the extraction of cadmium(II) by the organophosphorous extractant Cyanex 923 (L)
is based on the solvation mechanism of neutral HnCdCl(2+n) species and the formation of HnCdCl(2+n)Lq
complexes in the organic phase, where n=0, 1, 2 and q = 1, 2. The mathematical model of cadmium(II)
extraction was derived from the mass balances and chemical equilibria involved in the separation system.
The model was computed with the Matlab software. The equilibrium parameters for metal extraction,
i.e. the stability constants of the aqueous Cd–Cl complexes, the formation constants of the acidic Cd–Cl
species and the metal equilibrium extraction constants, were proposed. The optimized constants were
appropriate, as there was good agreement when the model was fitted to the experimental data for each
of the experiments.
Pramparo, L.; Stüber, F.; Font, J.; Fortuny, A.; Fabregat, A.; Bengoa, C. Journal of hazardous materials Vol. 177, num. 1-3, p. 990-1000 DOI: 10.1016/j.jhazmat.2010.01.017 Data de publicació: 2010-05-15 Article en revista
In this study, three different approaches for the covalent immobilisation of the horseradish peroxidase
(HRP) onto epoxy-activated acrylic polymers (Eupergit®C) were explored for the first time, direct HRP
binding to the polymers via their oxirane groups, HRP binding to the polymers via a spacer made from
adipic dihydrazide, and HRP binding to hydrazido polymer surfaces through the enzyme carbohydrate
moiety previously modified by periodate oxidation. The periodate-mediated covalent immobilisation
of the HRP on hydrazido Eupergit®C was found to be the most effective method for the preparation of
biocatalysts. In this case, amaximumvalue of the immobilised enzyme activity of 127 U/gsupport was found
using an enzyme loading on the support of 35.2 mg/gsupport. The free and the immobilised HRP were used
to study the elimination of phenol in two batch reactors. As expected, the activity of the immobilised
enzyme was lower than the activity of the free enzyme. Around 85% of enzyme activity is lost during
the immobilisation. However, the reaction using immobilised enzyme showed that it was possible to
reach high degrees of phenol removal (around 50%) using about one hundredth of the enzyme used in
the soluble form.
Stabilization/solidification (S/S) is one of the most employed techniques for treating liquid wastes containing heavy metals. Magnesium potassium phosphate cements have been used in recent years as stabilizing agents with positive results. However, little information is available about the retention of the metals by magnesium potassium phosphate cements matrices with the exception of the results of compliance tests. In this work, several pastes were prepared by reaction between low grade MgO and KH2PO4 in the presence of different heavy metal nitrate solutions (containing Cd(II), Cr(III), Cu(II), Ni(II), Pb(II) or Zn(II)). In all cases, the initial metal content of the dissolution was 25 g dm−3 and the oxide–phosphate ratio of the pastes was (50:50) in weight. Four different leaching tests were conducted on magnesium potassium phosphate cement pastes: simple batch test (EN 12457-2), equilibrium leaching test, availability test (NEN 7371) and acid neutralization capacity test (ANC). The metal leachate concentration was determined by means of ICP-MS. The stabilization of metals was successful in all cases, although the immobilizing system shows a better behaviour for Pb(II) and Cr(III) under acidic or neutral conditions.
Valderrama, C.; Arévalo, J.; Casas, I.; Martinez, M.; Miralles, N.; Florido, A. Journal of hazardous materials Vol. 174, num. 1-3, p. 144-150 DOI: 10.1016/j.jhazmat.2009.09.028 Data de publicació: 2010-02 Article en revista
Rozas, O.; Contreras, D.; Mondaca, M.A.; Pérez-Moya, M.; Mansilla, H. Journal of hazardous materials Vol. 177, num. 1-3, p. 1025-1030 DOI: 10.1016/j.jhazmat.2010.01.023 Data de publicació: 2010-01-13 Article en revista
Pseudo-emulsion based hollow fibre strip dispersion (PEHFSD) technique is Investigated for the permeation–separation of chromium from hydrochloric acid media. The permeation of Cr(VI) is investigated
in relation to various experimental variables: hydrodynamic conditions, the concentration of Cr(VI) and HCl in the feed phase, Cyanex-923 concentration, hydrazine sulphate as the stripping agent in the pseudo-emulsion phase. The performance of the PEHFSD was analyzed and optimum conditions are suggested for chromium separation from simulated industrial waste in a hydrochloric acid media.
Niubó, M.; Fernández , A.I.; Chimenos, J. M.; Haurie, L. Journal of hazardous materials Vol. 171, num. 1-3, p. 1139-1144 DOI: 10.1016/j.jhazmat.2009.06.126 Data de publicació: 2009-11 Article en revista
Buj, I.; Torras, J.; Casellas, D.; Rovira, M.; De Pablo, J. Journal of hazardous materials Vol. 170, num. 1, p. 345-350 DOI: 10.1016/j.jhazmat.2009.04.091 Data de publicació: 2009-10 Article en revista
Valderrama, C.; Alessandri, R.; Aunola, T.; Cortina, J.; Gamisans, X.; Tuhkanen, T. Journal of hazardous materials Vol. 166, num. 2-3, p. 594-602 DOI: 10.1016/j.jhazmat.2008.11.108 Data de publicació: 2009-07 Article en revista
Schwertmannite (Fe8O8(OH)5.5(SO4)1.25), jarosite (KFe3(SO4)2(OH)6) and goethite (FeOOH) control natural attenuation of arsenic in acid mine drainage (AMD) impacted areas. Batch experiments were conducted to examine the sorption capacity of synthetic goethite and synthetic jarosite at highly acidic pH (1.5–2.5), at two ionic strengths (0.02–0.15 mol dm−3, NaCl) and at sulphate concentrations in the range of 5 × 10−3 to 2.8 × 10−1 mol dm−3. In the absence of competitive effects of other anions, K-jarosite presents better removal efficiency than goethite for As(V). The maximum sorption capacity is estimated to be 1.2 × 10−4 and 7.0 × 10−6 mol m−2 for jarosite and goethite, respectively, under similar experimental conditions. The variation of arsenic sorbed on goethite as a function of the equilibrium arsenic concentration in solution fits a non-competitive Langmuir isotherm. In the case of K-jarosite, sorption data could not fit a Langmuir or Freundlich isotherm since sulphate–arsenate anion exchange is probably the sorption mechanism. Ionic strength and pH have little effect on the sorption capacity of goethite and jarosite in the small range of pH studied. The presence of sulphate, which is the main anion in AMD natural systems, has a negative effect on arsenic removal since sulphate competes with arsenate for surface sorption sites. Moreover, mobilization of arsenic in the transformation of schwertmannite to jarosite or goethite at pH 2–3 is proposed since the sorption capacities of goethite and K-jarosite are considerably lower than those reported for schwertmannite.
Castro, I.; Stüber, F.; Fabregat, A.; Font, J.; Fortuny, A.; Bengoa, C. Journal of hazardous materials Vol. 163, num. 2-3, p. 809-815 DOI: 10.1016/j.jhazmat.2008.07.054 Data de publicació: 2009-04-30 Article en revista