T. Salehi; D. Yousefi Kebria
Abstract
The present study focused on the synergistic effects bioremediation of phenol in aqueous solution using combination of anaerobic mixed culture and Granular Activated Carbon (GAC) as a biological GAC (BGAC). Meanwhile, the effect of contact time and various phenol concentrations on adsorption and ...
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The present study focused on the synergistic effects bioremediation of phenol in aqueous solution using combination of anaerobic mixed culture and Granular Activated Carbon (GAC) as a biological GAC (BGAC). Meanwhile, the effect of contact time and various phenol concentrations on adsorption and biosorption process investigated. The phenol concentration was analyzed using UV/Vis spectrophotometer. The morphology and structure of two adsorbents (GAC and BGAC) were characterized by FESEM and BET specific surface area analysis. The batch experiments using mixed bacterial culture, isolated from wood and paper factory wastewater, were adapted to high concentrations of phenol and employed in order to evaluate the tolerance and biosorption capability of microorganisms for phenol biodegradation. The synergetic effect of phenol removal using combination of GAC with an anaerobic biofilm indicated that the removal efficiency for concentration of 700, 800, and 1000 mg/l at initial stages increased to 4, 10, and 12%, respectively and while by increment of the retention time did not shown significant impact on the removal efficiency. These results conducted both desorption of adsorbates due to biotransformation in the aqueous solution and direct assimilation of adsorbates on GAC by the microorganism’s biofilm. The adsorption data were fitted with pseudo-first-order and pseudo-second-order models and it was found that the pseudo-second-order model explains the adsorption kinetics more efficiently. The compatibility of the Freundlich and Langmuir adsorption models to equilibrium data were investigated. In fact, the Langmuir isotherm was found to be the best fitting isotherm.
N. I. Ihimekpen; E. Atikpo; N. Kayode-Ojo; A. Michael
Abstract
The abilities of three indigenous bacteria for bioremediation of cadmium contaminated soils collected from Agbabu Farm Settlement close to mining sites in Ondo state, Nigeria was studied to provide helpful information for soils remediation and soils health management in this sub-region for Millennium ...
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The abilities of three indigenous bacteria for bioremediation of cadmium contaminated soils collected from Agbabu Farm Settlement close to mining sites in Ondo state, Nigeria was studied to provide helpful information for soils remediation and soils health management in this sub-region for Millennium Development Goals accomplishment. Bacillus subtilis, Proteus mirabilis, and Escherichia coli isolated from the soils were inoculated into different soil samples conditioned with optimized factors determined from the first phase experiments. The conditioned samples were experimented for residual cadmium concentration with time in days using Atomic Absorption Spectrophotometer. The soil cadmium attenuation from the initial concentration of 70.21 mg/kg to below the maximum allowable of 3 mg/kg was hard for the organisms. Bacillus subtilis performed correction at time 35 days with an efficiency of 96.10 % and residual concentration of 2.74 mg/kg. Proteus mirabilis and Escherichia coli with respective, high efficiencies of 85.05% and 79.35% failed. The removal rate capacities were -0.131d-1 for B. subtilis; -0.111d-1 for P. mirabilis; -0.105d-1 for E. coli. Four kinetic models fitted described the experimental data well. The models assessment revealed the removals to be transport controlled as diffusion process was the rate-controlling step.
Z. Ghorbani Kharaji; M. H. Fazaelipoor
Abstract
In this research five different solutions were used to wash an oil contaminated soil with the initial TPH (Total Petroleum Hydrocarbon) content of 46 g kg-1 (grams of TPH per kg of dry soil). The solutions were a basal mineral medium (solution I), the basal mineral medium inoculated with petroleum degrading ...
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In this research five different solutions were used to wash an oil contaminated soil with the initial TPH (Total Petroleum Hydrocarbon) content of 46 g kg-1 (grams of TPH per kg of dry soil). The solutions were a basal mineral medium (solution I), the basal mineral medium inoculated with petroleum degrading microorganisms (solution II), the basal mineral medium inoculated with a culture of petroleum degrading microorganisms and supplemented with a commercial washing powder (solution III), the basal mineral medium inoculated with the microorganisms and supplemented with Tween 80 (solution IV), and the basal mineral medium inoculated with the microorganisms and supplemented with sucrose (Solution V). Washing was performed by saturation of the soil with the solutions in columns and intermittent mixing. Solutions IV and V performed better than the others, giving more than 90% TPH removal in two months. In a separate experiment TPH removal was monitored as a function of time during washing. Solution V reduced the TPH content of the soil more rapidly than the others, with more than 70% TPH removal in 28 days. Addition of sand particles to the soil for the purpose of better mixing resulted in marginal positive effects.
A. Haghollahi; M. H. Fazaelipoor; M. Schafie
Abstract
This research work demonstrates the feasibility of accelerating bioremediation of a clay soil by supplementing with (NH4)2SO4, KH2PO4, sucrose (as an inducer for growth) and tween 80. The soil contained 7% residual gasoil. The bioremediation was stimulated by moisture adjustment to 10%, and inoculating ...
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This research work demonstrates the feasibility of accelerating bioremediation of a clay soil by supplementing with (NH4)2SO4, KH2PO4, sucrose (as an inducer for growth) and tween 80. The soil contained 7% residual gasoil. The bioremediation was stimulated by moisture adjustment to 10%, and inoculating with hydrocarbon degrading microorganisms. (NH4)2SO4 and KH2PO4 were added to the soil to obtain soil samples with C:N:P ratios of 100:1.4:1.4, 100:6.4:1.9, 100:11.4:2.4, and 100:21.4:3.4. The C:N:P of 100:11.4:2.4 resulted in more than 78% gasoil removal for duration of two months. Tween 80, in the range of 0-20mL/ (kg soil), was added to the soil samples with C:N:P ratio of 100:1.4:1.4. More than 84% removal was achieved when 10 mL/kg tween 80 was added to the soil. Sucrose, in the range of 0-20 g/(kg soil), was added to the soil samples with the C:N:P ratio of 100:1.4:1.4. For the sucrose level of 20 g/(kg soil), 79% removal was obtained in two months. Additional experiment was also conducted at two porosity levels of 54% and 22%. The removal percentage in the soil with high porosity was almost twice as compared to soil with low porosity.
