خيارات البحث
النتائج 391 - 400 من 62,595
The Effects of Nitrogen Fixing Tree (Leucaena leucocephala) and Mushroom (Pleurotus tuber-regium) on Spent Engine Oil Polluted Soil النص الكامل
2019
Adanikin, B. A. | Kayode, J.
Greenhouse experiment was conducted for four months using Leucaena leucocephala and Pleurotus tuber-regium to determine their bioremediation potentials. Leucaena leucocephala, Pleurotus tuber-regium and Leucaena leucocephala combined with Pleurotus tuber-regium were tested for their ability to improve nutrient (N, P, K, total organic carbon) and reduce heavy metals (Zn, Ni, Pb, Cu) of soil polluted with spent engine oil [5% (w/v)] and soil without spent engine oil was used as control. Bioaccumulation of nutrients and heavy metals in Leucaena leucocephala and Pleurotus tuber-regium were also determined. The highest reduction in Zn, Ni, Pb and Cu (41%, 48.39%, 61.60 and 52.72% respectively) were recorded in soil remediated with Leucaena leucocephala alone, reduction of 30.40%, 26.53%, 48.07% and 39.60% respectively were recorded in soil remediated with Pleurotus tuber-regium alone while in soil remediated with combined Pleurotus tuber-regium and Leucaena leucocephala, reductions of 32.7%, 33.43%, 88.41% and 46.22% respectively were recorded. Bioaccumulation of Zn, Ni, Pb and Cu in Leucaena leucocephala increased by 73.41%, 85.46%, 3366.04% and 125.53% respectively, similarly in Pleurotus tuber-regium by 30.16%, 21.67%, 71.11% and 53.21% respectively. These studies have shown that Pleurotus tuber-regium and Leucaena leucocephala are capable of bioremediating spent engine oil polluted soil although, treatment with Leucaena leucocephala alone tends to be most effective of these treatments.
اظهر المزيد [+] اقل [-]Solute Transport for Pulse Type Input Point Source along Temporally and Spatially Dependent Flow النص الكامل
2019
Yadav, R. R. | Kumar, L. K.
In the present study, analytical solutions are obtained for two-dimensional advection dispersion equation for conservative solute transport in a semi-infinite heterogeneous porous medium with pulse type input point source of uniform nature. The change in dispersion parameter due to heterogeneity is considered as linear multiple of spatially dependent function and seepage velocity whereas seepage velocity is nth power of spatially dependent function. Two forms of the seepage velocity namely exponentially decreasing and sinusoidal form are considered. First order decay and zero order production are also considered. The geological formation of the porous medium is considered of heterogeneous and adsorbing nature. Domain of the medium is uniformly polluted initially. Concentration gradient is considered zero at infinity. Certain new transformations are introduced to transform the variable coefficients of the advection diffusion equation into constant coefficients. Laplace Transform Technique (LTT) is used to obtain analytical solutions of advection-diffusion equation. The solutions in all possible combinations of temporally and spatially dependence dispersion are demonstrated with the help of graphs.
اظهر المزيد [+] اقل [-]Evaluating the effectiveness of Tamarindus indica partially activated seed coat biomass in removing of nitrates from aqueous solutions النص الكامل
2019
Srinivasulu, D. | Naidu, GRK | P. K., Pindi
Biomass derived from Tamarindus indica partially activated seed coat was investigated for the removal of nitrate ions from aqueous solutions. Batch experiments were performed to evaluate the parameters like pH, contact time, sorbent dose and initial nitrate concentration. pH of the solution played vital role. The maximum sorption observed at pH=7, sorbent dose 300mg, contact time at 120min, initial nitrate concentration 5mg. Physicochemical properties of the biomass were evaluated using scanning electron microscopy (SEM), energy dispersive X-ray analysis and Fourier Transform infra red (FTIR) spectroscopy. The SEM and FTIR data reveals the suitable surface and the presence of chemical functional groups such as hydroxyl, amide, carbonyl strong acid and primary amine on the biosorbent surface contributes to biosorption. The equilibrium isotherms and kinetics were deliberated. Biosorption equilibrium followed Langmuir isotherm. Pseudo second order kinetics provided better correlation of the experimental data in comparison with pseudo-first-order kinetic model. The study indicated that Tamarindus indica partially activated seed coat biomass found to be a novel biosorbent for the removal of nitrates from aqueous solutions.
اظهر المزيد [+] اقل [-]Model for the Treatment of Refinery Wastewater and expression of catabolic genes in Fluidized Bed Bioreactor using mixed bacterial consortium النص الكامل
2019
Ajao, A. T. | Mustapha, M. O. | Yakubu, S. E.
This study was undertaken to evaluate a novel aerobic wastewater treatment model for the remediation of refinery effluents and to assess the removal efficiency of Bulkholderia cepacia strain AJI and Corynebacterium kutscheri strain AJ2 to clean oil waste from petrochemical company. Wastewater quality parameters including pH, BOD5, COD, TDS, OIL & GREASE, PHENOL concentration, TPH and THC were monitored at 5, 10 and 15 days of treatment and the removal efficiencies were calculated. Results indicated that the raw oily wastewater effluents used during this study had extremely high levels of all the tested parameters. The mean values of all physicochemical parameters of the wastewater from primary tank at different treatment period were statistically different (P˂0.001) After 15 days of biological treatment, BOD5 ,COD, TDS, Phenol, TPH, Oil & grease level of the refinery wastewater were reduced by 95.60 %, 98.40 % , 66.34 % , 100 %, 97.60 % and 96.20 % respectively. The detection of the catabolic genes in the bacterial isolates recovered from primary tank using polymerase chain reaction revealed that both Bulkholderia cepacia strain AJ1 and Corynebacterium kutsheri strain AJ2 carried alk B and C23O but C12O was not detected in both isolates. Naphthalene dioxygenase was detected in Bulkholderia cepacia strain AJ1 but not found in Corynebacterium kutscheri strain AJ2. After treatment the waste water was filtered in the secondary tank. The results of physicochemical parameters in the outlet vessel essentially confirmed that the mixed culture in the two column model successfully carry out bioremediation of refinery wastewater. Therefore, aerobic treatment model for the bioremediation of refinery Petroleum refineries generate great amounts of wastewaters that may become seriously dangerous, leading to the accumulation of toxic products in the receiving water bodies with potentially serious long term effects to aquatic biota. Due to extreme toxicity of contaminants in refinery wastewater, there is a need to develop an economical technique to remove the pollutants from the wastewater is highly recommended owing its environmental friendliness.
اظهر المزيد [+] اقل [-]Verification of IVE Model for SAIPA Co. Fleet Emission النص الكامل
2019
Alipourmohajer, Sh. | Rashidi, Y. | Atabi, F.
To determine the amount of air pollutants, produced by Iranian automakers, and compare it with old and retrofitted vehicles have become one of the important tools of urban management. The present research uses International Vehicle Emission (IVE) modeling software in order to verify SAIPA Co. fleet emissions, based on Euro 4 emission standard (SAIPA Co. recognized as a superior Iranian brand in vehicle industry). There has been attempts to determine pollutant emission from Saipa Co.-manufactured cars in the city of Tehran, in accordance with Tehran Driving Cycle along with modeling and lab results which have over 90% conformity with modeling and lab results of New European Driving Cycle. According to ISQI’s 100,000-km test results, the amount of CO2 emission modeling from X100 and Tiba2’s has been about 160 gr/km, which has been within the range, whereas the modeled CO2 emission rate has been 232 gr/km in TDC, i.e., 1.5 times more than laboratory test, due to different driving cycle usage. Significant differences between the values obtained in the emission lab and modeling at New European Driving Cycle, Tehran Driving Cycle, and Tehran Air Quality Control Company report, indicate that relying on hypothetical situation leads to inapplicable emissions value from light vehicles.
اظهر المزيد [+] اقل [-]Influential Factors of Air Pollution Awareness in Isfahan, Iran النص الكامل
2019
Yazdanibakhsh, F. | Salehi, E. | Faham, E. | Amin, M. M.
The main objectives of the present study are to both evaluate the level of awareness about air pollution and examine the determinants, likely to affect this awareness. As a result, it discusses influential factors on air pollution awareness, presenting findings from a case study, conducted in the city of Isfahan, Iran, wherein 400 individuals have been selected via proportional random sampling and the data has been collected by means of a questionnaire, provided by the authors, the validity of which has been confirmed by a panel of experts. As for the assessment of the questionnaire’s reliability, this study has used Cronbach's alpha to find out that it has been beyond 0.7 for all variables. The data have been analyzed, using descriptive and inferential statistics, such as the extent of mean, standard deviation, the coefficient of variation, correlation analysis, and regression analysis. Results from the latter show that level of education, level of using information sources, membership, motivation, and participation could explain 50% of the variations in the level of awareness concerning air pollution.
اظهر المزيد [+] اقل [-]Monitoring of SO2 column concentration over Iran using satellite-based observations during 2005-2016 النص الكامل
2019
Salmabadi, H. | Saeedi, M.
For the first time, sulfur dioxide concentration was monitored between 2005 and 2016 over Iran which is among the countries with a high SO2 emission rate in the world. To that end, SO2 column concentration at Planetary Boundary Layer (PBL) from Ozone Monitoring Instrument (OMI) was analyzed. OMI is a sensor onboard the Aura satellite which can measure daily SO2 concentration on the global scale. From OMI maps, 19 notable SO2 hotspots were detected over Iran. The results indicate that the most elevated level of SO2 among these 19 hotspots belong to Khark Island and Asaluye in Bushehr province, southwest of Iran. Annual trend analysis shows that SO2 concentration has been slightly augmented during 2005-2016 over this country. Distribution analysis of SO2 concentration over Iran showed that the most polluted provinces are Bushehr, Khuzestan and Ilam lied in the southwest of Iran. On the contrary, the lowest level of SO2 has observed over northwest of Iran at West and East Azerbaijan and Ardabil provinces. The correlation coefficient between total energy production in Iran and SO2 concentration from 2005 to 2016 is as high as ~0.7. Hence, it can be derived that energy production, most notably production of crude oil, plays a pivotal role in SO2 concentration over Iran.
اظهر المزيد [+] اقل [-]Liquid Effluent Discharge and Control Management of Surrounding Soil النص الكامل
2019
Hussein, H. M. | Ayub, S. | Siddiqui, A. A.
The effluent generated from a thermal power plant waste is a mixture of several chemicals and to identify the effect of these chemicals on soil, a case study on naturally contaminated sites at Al-Musayyib region, Hilla city in Iraq has been carried out. Soil and water samples were collected from the sites and analyzed to identify the pollutants and their effect on soil characteristics. Laboratory experiments were formulated to model the field around a channel collecting effluent for about 20 years and the pollutant transport pattern through the soil using soaking process was studied. Experiments were also conducted to study the effect of pollutants on engineering properties of the soil. For environmental management, permeable reactive barriers are used as stabilization and solidification technology to control the pollution through the soil. In this study, the suitability of locally available materials like activated granular carbon was also investigated as reactive media in permeable reactive barrier. The results have shown higher change in geo-environmental properties of soil with the soaking period and it has also been proved that granular carbon improves the geo-environmental properties of polluted soil.
اظهر المزيد [+] اقل [-]Bioremediation of Cadmium by Mixed Indigenous Isolates Serratia liquefaciens BSWC3 and Klebsiella Pneumoniae RpSWC3 Isolated from Industrial and Mining Affected Water Samples النص الكامل
2019
Kumar, P. | Gupta, S. B. | -, Anurag | Soni, R.
A total of 58 Cadmium tolerant bacterial isolates were isolated from 26 samples collected from 20 villages/city of different contaminated water samples from industrial and mining affected areas of Chhattisgarh (India). Out of 58 bacterial isolates, 15 bacterial isolates were able to grow in presence of 40 mM cadmium chloride. These fifteen were further screened by biochemical characterization, antibiotic susceptibility and presence of czcA gene. However, finally five selected isolates (BSWC3, RgCWC2, RgUWC1, RpSWC3, KDWC1) were identified by 16S rRNA gene sequencing belonged to the genus Serratia liquefaciens, Klebsiella quasipneumoniae subsp. similipneumoniae, Klebsiella pneumoniae, Pantoea dispersa and Enterobacter tabaci, respectively. Among these two best culture Serratia liquefaciens BSWC3 and Klebsiella pneumoniae RpSWC3 were testes for their bioremediation efficiency individually as well as in mixed culture. Atomic Absorption spectrophotometer analysis of samples revealed that cadmium (Cd) tolerant bacterial isolates BSWC3, RpSWC3 and Combination of BSWC3 and RpSWC3 were significantly reduce of cadmium concentration i.e. 44.46%, 40% and 50.92%, respectively as compared to control. Therefore, the finding of the present study revealed the use of mixed culture or consortium of indigenous isolates is the better option for bioremediation of heavy metals.
اظهر المزيد [+] اقل [-]The Evaluation of Tropospheric Ozone Formation in the Downwind of the South Pars Industrial Zone النص الكامل
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.
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