Sharif Digital Repository

Petroleum contamination of soil is a serious problem throughout the oil producer countries. Vegetation may play an important role in the biodegradation of toxic organic chemicals in soil. For petroleum compounds, the presence of rhizosphere micro flora may accelerate biodegradation of the contaminants. In a greenhouse study, petroleum contaminated soil were treated using phytoremediation . The C/N ratios and microbial populations were assessed in the beginning and the end of trials. The results showed that Puccinellia distance could tolerate the harsh condition of the soils. As MPN increases, C/N ratios decrease among trials. N, as a nutrient, had effects on both microbial populations and... 

In this study, the Geocoat™ technology was used for the extraction of zinc from a mineral concentrate obtained from the Kooshk mine (Yazd, Iran) by a culture dominated by the mesophilic bacterium Acidithiobacillus ferrooxidans in a packed column bioreactor. A low grade sphalerite ore was used as support for the concentrate coating. During the 100 days of leaching pH, Fe3+, Fetotal, microbial population density and zinc extraction were measured. The final zinc extraction from concentrate and low grade support was 97% and 78%, respectively, and it was found that leaching from the support does not proceed significantly before leaching from the coating is completed  

Petroleum contamination of soil is a serious problem throughout oil-producing countries. One of the cost-effective options for removing contaminants from shallow soils is phytoremediation. Vegetation, by stimulating the microorganisms via releasing root exudates near the rhizosphere, may play an important role in the biodegradation of toxic organic chemicals in soil. This experiment investigates the efficiency of this emerging technology following the implementation of five plant species. The study was carried out in a greenhouse using crude oil-contaminated soil from sites around the Tehran Refinery. To study the effect of a water-absorbent agent, we also used hydrogel in this experiment.... 

This research aims to improve simultaneous nitrification-denitrification and phosphorus removal (SNDPR) using novel carriers and to demonstrate the effect of carrier characteristics on nutrient removal in a biofilm reactor. For this purpose, biofilms enriched with both polyphosphate-accumulating organisms (PAOs) and nitrifiers were cultivated in two parallel sequencing batch reactors containing conventional moving bed bioreactor carriers (MBBR) and a novel type of carriers (carbon-based moving carriers (CBMC)). The new carriers were produced based on recycled waste materials via a chemical-thermal process and their specific surface area were 10.4 times higher than typical MBBR carriers of... 

Bacterial transport parameters play a fundamental role in microbial population dynamics, biofilm formation and bacteria dispersion. In this study, the novel model was extended based on the capability of microsized microbial fuel cells (MFCs) as amperometric biosensors to predict the cells' chemotactic and bioelectrochemical properties. The model prediction results coincide with the experimental data of Shewanella oneidensis and chemotaxis mutant of P. aeruginosa bdlA and pilT strains, indicating the complementary role of numerical predictions for bioscreening applications of microsized MFCs. Considering the general mechanisms for electron transfer, substrate biodegradation, microbial growth...