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Radiological dose Assessment by Means of a Coupled WRF-HYSPLIT Model under Normal Operation of Bushehr Nuclear Power Plant Texto completo
2019
Feyzinejad, M. | Malakooti, H. | Sadrinasab, M. | Ghader, S.
In the present work WRF model is used to generate meteorological fields for the HYSPLIT dispersion model. Sensitivity and validation of the WRF model, is conducted by utilizing different combinations of physical parameterization schemes. For this purpose, eight different configurations are examined. Assessment of the predictions of the WRF model is carried out by computing the statistical parameters including correlation coefficient (CC) and root mean square error (RMSE). As an example of the results of the WRF model utilizing proper physical configuration at Bousher syoptic station at 03/01/2005 leads to CC=0.82007 and RMSE=1.91783 for wind speed parameter. Once the proper configuration of the WRF model is obtained, dispersion simulations and annual effective dose for adult age group are carried out by WRF-HYSPLIT coupled model under normal conditions for Bushehr power plant. Simulated annual effective dose for adult age group by the coupled model for the years 2014, 2015 and 2016 are 5.8E-08 Sv/yr, 6.7E-08 Sv/yr and 1.1E-07 Sv/yr respectively. Results show that simulation and prediction of effective dose with coupled WRF-HYSPLIT model are in good agreement with observations and indicates the validity of the simulations. The ratio of predicted annual effective dose to dose limit (1E-04 Sv/yr) for normal operation is obtained less than 0.2 percent (
Mostrar más [+] Menos [-]Evaluation of Applying Solvent Extraction and Iron Nanoparticles for Oily Sludge Recovery and Upgrading Based on Sludge Specifications Texto completo
2019
Nezhadbahadori, F. | Abdoli, M. A. | Baghdadi, M.
Due to its wide range of hazardous hydrocarbons and even heavy metal ions, oily sludge has become a great environmental challenge which must be dealt with quite quickly. As a result, ther have been numerous efforts during recent years to develop an efficient method for sludge recovery. The current research studies the effectiveness of solvent extraction with toluene and Fe2O3 nanoparticles for recovery and upgrading of oily sludge. Having employed Design of Experiment (DOE), it has found optimum conditions for sludge recovery with solvent extraction, namely a temperature of 55°C and mixing time of 17 minutes with solvent to sludge ratio of 6.4/4.2. Under these conditions, the sludge recovery has been 37%, which is the maximum available with toluene. Furthermore, it has studied the effectiveness of Fe2O3 nanoparticles for improvement of sludge pyrolysis efficiency in order to upgrade the oily sludge, wherein it has been observed that nanoparticles can significantly decrease the temperature and time of reaching maximum conversion during sludge pyrolysis process. The temperature and time of reaching to the maximum conversion, by means of gamma Fe2O3 nanoparticles, is about 200°C and 1200 s, respectively, which is lower than the condition in which pure sludge is being pyrolyzed.
Mostrar más [+] Menos [-]Application of Hybrid Cells in Series Model in the Pollution Transport through Layered Material Texto completo
2019
Chabokpour, J.
The present paper aims at investigating the applicability of hybrid cells in the series model for pollution transport inside the layered porous media. For this purpose, four layers of rock material have fallen inside the experimental flume, with eight sensors installed longitudinally inside the media to obtain experimental BTCs. In order to measure time parameters of the model, named , two different methods of LSCF and MM have been examined. The model's sensitivity as well as its temporal equations with different parameters have been assessed. Finally, results show that at the fixed time step, the model is more sensitive to parameter (advection zone time parameter) rather than residential time parameters, to which the moment relations are more sensitive. A detailed computation of the related transport parameters has been operated and the Peclet number, crossing velocity, dispersion coefficient, time to the max, and maximum concentration have been calculated. Eventually, the model's applicability for large-scale porous media has been proven with only one unit of the cells.
Mostrar más [+] Menos [-]Study of Cadmium and Nickel Removal from Battery Industry Wastewater by Fe2O3 Nanoparticles Texto completo
2019
Shahriari, T. | Mehrdadi, N. | Tahmasebi, M.
Nickel and cadmium usually enter the environment and water resources through wastewater, released by various industries, and may have adverse effects. The current study employs α–Fe2O3 nanoparticles of 20-40 nm in order to remove nickel and cadmium from the wastewater of Saba Battery Company. Also, it investigates the influence of effective parameters on adsorption process, including pH, contact time, and the adsorbent rate so that it can optimize the adsorption process. The maximum adsorption rate of nickel and cadmium can be observed in pH ranges of 5 to 9. In addition, adsorption rates for nickel (at pH = 7) and for cadmium (at pH = 5) have been 92.98% and 93.97%, respectively. By increasing the adsorbent rate, the adsorption grows, due to the increase in absorbate surface area, and an optimum adsorbent rates of 0.15 g and 0.2 g are obtained for cadmium and nickel, respectively. The maximum nickel and cadmium adsorption rates occur during the first 60 min of contact with nanoparticles. In this study, adsorption kinetics and isotherms have also been investigated and it has been found that the adsorption kinetics of both nickel and cadmium ions follow the pseudo-second-order model, while adsorption isotherms of nickel and cadmium follow the Freundlich model.
Mostrar más [+] Menos [-]Review on Bioremediation: A Tool to Resurrect the Polluted Rivers Texto completo
2019
Shishir, T. A. | Mahbub, N. | kamal, N. E.
The term bioremediation describes biological machinery of recycling wastes to make them harmless and useful to some extent. Bioremediation is the most proficient tool to manage the polluted environment and recover contaminated river water. Bioremediation is very much involved in the degradation, eradication, restriction, or reclamation varied chemical and physical hazardous substances from the nearby with the action of all-inclusive microorganisms. The fundamental principle of bioremediation is disintegrating and transmuting pollutants such as hydrocarbons, oil, heavy metal, pesticides and so on. Different microbes like aerobic, anaerobic, fungi and algae are incorporated in bioremediation process. At present, several methods and approaches like bio stimulation, bio augmentation, and monitoring natural recovery are common and functional in different sites around the world for treating contaminated river water. However, all bioremediation procedures it has its own pros and cons due to its own unambiguous application. Above all, utilization of bioremediation paving a minimal inconsiderably contaminated, healthy as well as safe and sound future.
Mostrar más [+] Menos [-]Synthesis of Activated Carbon from Sugarcane Bagasse and Application for Mercury Adsorption Texto completo
2019
Javidi Alsadi, k. | Esfandiari, N.
With the growth and development of chemical plants, the amount of mercury released in wastewater has increased. Mercury in wastewater contains harmful compounds which are hazardous to the human health and living organisms. Therefore, its removal from wastewater is significant. There are various techniques or methods available for removing mercury from aqueous solutions. This study focused upon the removal of mercury from aqueous solution with commercial activated carbon and activated carbon from sugarcane bagasse. Activated carbon produced from sugarcane bagasse was used as adsorbent. This adsorbent was used to remove mercury from aqueous solution. For this purpose, first, the optimal mercury solution pH for mercury removal was obtained. Effective parameters such as contact time, initial concentration of mercury, adsorbent dose and agitation speed were investigated. The mercury adsorption was increased when the mass of activated carbon was increased. Increasing the initial mercury concentration leads to decrease in mercury adsorption efficiency. The results of experiments indicated that the speed of the stirrer was not considered to be an effective factor in the mercury adsorption. Experiments were also carried out on a commercial activated carbon. Adsorption results obtained for sugarcane bagasse activated carbon were compared with commercial activated carbon. The adsorption efficiency was increased as the contact time was increased. Finally, the experiment was carried out on water samples released from South Pars platforms. In addition to the mercury removal, other heavy metals removal such as lead and cadmium were also carried out.
Mostrar más [+] Menos [-]Evaluation of Ecological Vulnerability in Chelgard Mountainous Landscape Texto completo
2019
Darabi, H. | Islami Farsani, S. | Irani Behbahani, H.
Although complexity and vulnerability assessment of mountain landscapes is increasingly taken into consideration, less attention is paid to ecophronesis-based solutions so as to reduce the fragile ecosystem vulnerability. The main propose of this study is to provide an insight of mountain complex landscape vulnerability and propose ecophronesis-based solutions in strategic planning framework for reduction of vulnerability. The study has been carried out by following five steps in Chelgard Mountain landscapes (center of Iran): First, it determines the evaluation framework on basis of rapid literature review. Second, the vulnerability is assessed, using Analytic Hierarchy Process (AHP), in accordance with experts’ opinion. In the third step, the results provide a zoning map of vulnerability. Afterwards, the study suggests a strategic plan to manage the area environmentally and, finally, the solutions are proposed, based on ecophronesis, in order to not only solve the plight but also reduce the vulnerability. Results from the vulnerability assessment indicate that anthropogenic stressors intensify the vulnerability. While local ecological wisdom is shaped over time in the area, its application faces challenges as a result of rapid and immense socio-economic changes. It seems that sustainability of mountain ecosystem needs to regenerate social structures on basis of socio-ecological capital. Main characteristics of these adopted social structures include their balance with the ecosystem and adoption with new lifestyles.
Mostrar más [+] Menos [-]Novel Bacterial Strains Pseudomonas sp. and Bacillus sp. Isolated from Petroleum Oil Contaminated Soils for Degradation of Flourene and Phenanthrene Texto completo
2019
Bharti, V. | Gupta, B. | Kaur, J.
Flourene and phenanthrene are organic compounds with high hydrophobicity and toxicity. Being recalcitrant in nature they are accumulating in the environment at an alarming concentration, posing serious threat to living beings. Thus in the present study, microorganisms were screened for their ability to degrade these contaminants at high concentrations in least period of time. Two out of fifteen isolates screened showed growth in basal medium containing 25 mg/l of fluorene/phenanthrene as the only carbon source. These selected isolates were acclimatised with step wise increased concentrations of flourene/phenanthrene for 165 days in basal medium. The acclimatised strains were identified and characterised on the basis of their morphological and biochemical characteristics and 16S rRNA gene sequence analysis. Results showed close relatedness of the isolates to Pseudomonas aeruginosa sp. and Bacillus safensis sp. Biodegradation studies carried out with these acclimatised strains at optimum conditions (pH 7 and temperature 30°C) showed 62.44% degradation of fluorene and 54.21% of phenanthrene in 10 days by Pseudomonas sp. VB92, whereas, Bacillus sp. JK17 degraded 43.64% of fluorene and 59.91% of phenanthrene in 12 days, at an initial concentration of 200 mg/l, as determined by HPTLC. During fluorene degradation by Pseudomonas sp. VB92, one metabolite was identified as fluorene,1,4-dihydro. An anionic biosurfactant (emulsification index of 80%) produced by strain VB92 during growth with PAHs, improved its degradation rate. This showed strong potential of the acclimatised strains for bioremediation and reclamation of polyaromatic hydrocarbon contaminated sites.
Mostrar más [+] Menos [-]Comparative Study on the Remediation Potential of Panicum Maximum and Axonopus Compressus in Zinc (Zn) Contaminated Soil Texto completo
2019
Ukoh, S.N.B. | Akinola, M.O. | Njoku, K.L.
Soil contamination by heavy metals has increased noticeably within the past years. Unlike organic compounds, metals cannot degrade; therefore effective cleanup is required to reduce its toxicity. This experiment was undertaken to investigate the comparative potential of Panicum maximum and Axonopus compressus to bioremediate zinc polluted soils, the impact of Zn on the antioxidant defense system of the plant, assaying for activities of antioxidants proteins. Zinc salts were mixed with soil at various concentrations 5 mg/kg, 10 mg/kg, 20 mg/kg and 40 mg/kg in triplicates and control was setup. After 4 months, the plants (root, shoot and leaf) and soil were analyzed for morphological, biochemical parameters and Zn concentration. The root length of P. maximum and A. compressus decreased as the concentration of zinc increased. The least shoot length inhibition of A. compressus was 6.16% (5 mg/kg) while the highest shoot length inhibition was 40.14% (40 mg/kg). The least shoot length inhibition of Panicum maximum was 6.16% exposed to 5 mg/kg and the highest shoot length inhibition was 53.13% (40 mg/kg). There was significant reduction of the heavy metals in vegetated soils for P. maximum and A. compressus at the end of the study compared to the heavy metals in the soils at the beginning of the study (p<0.05). P. maximum, is a better removal of Zn than A. compressus, however, it was not significant. Glutathione levels varied significantly (p≤ 0.05) with respect to heavy metals. A. compressus has more effects on Glutathione activities than P. maximum. Zn caused a decrease in metallothionein level in P. maximum while A. compressus metallothionein level increased.
Mostrar más [+] Menos [-]Effect of Heavy Metals on the Growth of Total Phytoplankton Load Texto completo
2019
Khatun, M. | Alam, A. K. M. R.
The experiment was performed to evaluate effect of heavy metals on total phytoplankton load (TPL) using water of Turag River adjacent to Ashulia locating on the north-eastern side of Dhaka city, Bangladesh. Total phytoplankton load comprises of Euglena sp., Borodinella sp., Pediastrum biradiatum, Pinnularia sp., Fragillaria sp., Fragillaria crotonensis, Gloeocapsa sp., Navicula sp., Cynedra sp., Crucigenia sp., Chlorella sp., Spirogyra sp., Phacus acuminatus, Phacus circulatus., Nitzschia sp. and Nitzschia clausii. Phytoplankton load showed the abundances Bascillariophyceae (43.75%) > Chlorophyceae (37.50%) > Euglenophyceae (18.75%). The average maximum growth rate (log transformed) of TPL in control culture was -0.25μg/l and treated cultures using 1ppm, 3ppm, 5ppm, 7ppm concentration of heavy metals (Zn and Cu) were 0.03 μg/l, 0.03 μg/l, -0.11 μg/l and -0.26 μg/l, respectively. In treated culture using 1ppm concentration of heavy metals (Zn and Cu) the growth rate of phytoplankton load increased significantly whereas the growth rate decreased at higher concentrations (3ppm, 5ppm and 7ppm) of heavy metals. The implication of this finding can be used to monitor health of riverine ecosystems and management of river pollution.
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