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Degradation of Hydrocarbons and Lignin-like compounds by Alcaligenes sp. strain 3k isolated from Ilorin
2019
Adetitun, D. O. | Fathepure, B. | Hugh, H. | Kolawole, O. M. | Olayemi, A. B.
The primary goal of this study was to isolate hydrocarbon-degrading organisms and assess their ability to bioremediate petroleum-contaminated soil and water. Nigeria is one of the major oil producing countries and petroleum contamination is widespread in agricultural soil. Alcaligenes sp. strain 3k was isolated from a kerosene-polluted soil in Ilorin, Nigeria. We also assessed its ability to degrade plant lignin, as lignin is a complex aromatic heteropolymer commonly found in soil and aquifer environment. Strain 3k was originally grown on mineral salts medium with kerosene as a sole energy and carbon source. The capacity of the isolate to degrade both aromatic, aliphatic hydrocarbons and lignin-like compounds was tested. Among the tested compounds, the organism utilized kerosene, hexadecane, cyclohexane, phenol and benzoate as the sole sources of carbon. In addition, strain 3k also degraded various lignocellulose compounds as the sole source of carbon. However, hexane, benzene, toluene, ethylbenzene and xylene were not metabolized. Our study demonstrates that soil organisms like Alcaligenes could play important role in the reclamation of petroleum-contaminated soil and water. Utilization capacity of lignin as the sole carbon source suggest that these organisms can survive on plant detritus and also have the ability to degrade hydrocarbons upon accidental or deliberate contamination of agricultural soil and water.
显示更多 [+] 显示较少 [-]The Evaluation of Tropospheric Ozone Formation in the Downwind of the South Pars Industrial Zone
2019
Moradzadeh, M. | Ashrafi, k. | Shafiepour-Motlagh, M.
Hydrocarbon Processing Industries (HPIs) emit large amounts of highly reactive hydrocarbons and Nitrogen Oxides to the atmosphere. Such simultaneous emissions of ozone precursors result in rapid and high yields ozone (O3) formation downwind. The climate of the Middle East has been shown to be favorable for O3 formation in summer. There are also vast activities in processing oil and gas in this region. This study aimed to investigate the influence of HPIs located in the Middle East on ozone formation. We chose the South Pars Zone (SPZ) located in the coastal area of the Persian Gulf with concentrated HPIs as a case study. To do this, after developing an emission inventory for O3 precursors, we used OZIPR, a Lagrangian photochemical model, coupled with SAPRC-07 chemical mechanism to describe the effects of HIPs on ozone formation in the SPZ and downwind area from June to August of (2017). Results indicate that the SPZ has a far-reaching and wide-ranging impact on O3 formation in downwind areas and an area at a distance of 300 km can be affected profoundly (Average 0.06 ppm and maximum increase 0.24 ppm). Given the large numbers of HPIs located in the Middle East, we predict that the transport of O3 and its precursors from this region play an important role in the ozone air pollution in a much wider area and the role of these industries should be taken into account for regional and interregional ozone concentration modeling.
显示更多 [+] 显示较少 [-]Radiological dose Assessment by Means of a Coupled WRF-HYSPLIT Model under Normal Operation of Bushehr Nuclear Power Plant
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 (
显示更多 [+] 显示较少 [-]Improvement of Anaerobic Digestion of Sewage Sludge, Using Combined Hydrogen Peroxide and Thermal Pre-Treatment
2019
Hallaji, S. M. | Siami, S. | Aminzadeh, B.
The present study investigates the influence of individual and combined hydrogen peroxide and thermal pre-treatment of waste activated sludge on anaerobic digestion. For so doing, it employs anaerobic batch reactors in the mesophilic conditions. For comparison, soluble fractions of organic matter, biogas production, biochemical methane potential, removal of chemical oxygen demand (COD), and volatile solids (VS) have been measured during the anaerobic digestion process in systems with and without pre-treatment. Hydrogen peroxide pre-treatment has been tested in two concentrations of 30 g H2O2/kg VS and 60 g H2O2/kg VS and thermal pre-treatment has been performed at two temperatures of 75℃ and 90℃. According to the results, the solubalisation of organic matter considerably improves, when combined hydrogen peroxide and thermal pre-treatment is employed. As a result, in comparison to the control reactor, higher amounts of biogas (71%) and methane (81%) have been produced in the bioreactor, pre-treated with combined hydrogen peroxide (30 g H2O2/kg VS) and heat (90 ℃). In addition, the removal efficiency of COD and VS from the digested sludge has been enhanced in the pre-treated reactors (up to 39% and 92%, respectively) in comparison to the control reactor. The improved methane yield, COD, and VS are of paramount importance, not only because higher amounts of renewable energy are obtained from the anaerobic digestion process, but because sludge transport costs are reduced and the digested sludge obtains a higher potential application to agricultural lands.
显示更多 [+] 显示较少 [-]Study of Cadmium and Nickel Removal from Battery Industry Wastewater by Fe2O3 Nanoparticles
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.
显示更多 [+] 显示较少 [-]Stabilization of Filter Cake and its Leaching Behaviour: A Case Study with Cementitious and Soluble Phosphate Additives
2019
Shirdam, R. | Nourigohar, A. | Mohamadi, S.
Filter cake is one of the main waste products of zinc processing industries and it contains a high amount of toxic heavy metals. In this research in order to reduce heavy metals leachability in filter cake, Portland cement, natural pozzolan, diammonium phosphate (DAP), triple superphosphate (TSP), lime, zinc oxide and ground granulated blast furnace slag (GGBFS) have been used. This research’s results suggest that even though leachability of lead in the filter cake is quite low, it should be noted that limestone doubles the solubility level of Pb due to the mineralogical nature of the waste, by converting its sulphate form (PbSO4) to its carbonate form (PbCO3), which is more soluble. TSP was the only additive capable of reducing the leachability of metal elements in the filter cake as well as stabilizing the amounts of Pb and Cd in TCLP extracts within the limit. Although all additives were able to reduce Cd leachability, TSP and ZnO had the most remarkable efficiency. According to XRD results, the main factor in lead stabilization using TSP was a reduction in the amount of PbSO4 (with high Ksp) and an increase in PbS (with low Ksp), which ultimately reduced lead leachability. The Pozzolan which was used for the first time as a stabilizer demonstrated a good performance in reducing the leachability of Cd, Ni and Cu. In addition, due to the pseudo-cementitious properties of Pozzolan, it can reduce leachability of metal elements, along with other additives such as cement, by increasing the solidification efficiency.
显示更多 [+] 显示较少 [-]Review on Bioremediation: A Tool to Resurrect the Polluted Rivers
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.
显示更多 [+] 显示较少 [-]Strategic Planning, Based on Environmental Spatial Assessment, Using SWOT and GIS to Locate Sustainable Industrial Areas (Case Study: Tehran Province)
2019
Hoveidi, H. | Nasehi, S. | Imanpour, Namin | Nohegar, A.
Unbalanced distribution of population in a country like Iran as well as accelerating urbanization and environmental degradation, both arising from incorrect location of industrial areas, are two problems that require appropriate industrial development policies to get resolved. Considering the expansion of industrial areas along with their role in contamination of the environment, it is necessary to develop strategies to improve environmental performance. The purpose of this study is to provide strategies for establishment of industrial areas, based on environmental spatial assessment, using SWOT technique and GIS. In this method, once the spatial data are mapped and analyzed with GIS software, leading to determination of effective factors for location of industrial areas and their, the maps of such effective factors can be prepared. After weighing effective layers on location, based on the AHP model, the GIS software capabilities have been used to merge and overlap the maps and the industrial areas location map are prepared. The map has been classified in five classes (very poor, poor, moderate, good, and very good) and finally, based on the final map and SWOT analysis, optimal strategies have been developed to reduce environmental degradations. The location analysis with integrated GIS and SWOT method is effective for providing optimal strategies. More accurate results of this study show that the study area is located in "defensive" position and the authorized areas to locate the industrial areas in the "very good" class are over 240,191.9 hectares large, being mostly in the south and southwest of Tehran.
显示更多 [+] 显示较少 [-]Evaluation of Ecological Vulnerability in Chelgard Mountainous Landscape
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.
显示更多 [+] 显示较少 [-]Comparative Study on the Remediation Potential of Panicum Maximum and Axonopus Compressus in Zinc (Zn) Contaminated Soil
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.
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