Sharif Digital Repository

Biodegradation has always been as a proper method for treatment of oil contamination. Accordingly, several investigations have been done by mesophilic bacteria for biodegradation of hydrocarbons while few studies have been conducted about thermophilic bacteria.
There are many factors like high growth rate of thermophilic bacteria and good resistance of enzymes secreted from thermophiles against physical and chemical variations lead to the extensive use of thermophilic bacteria for removal of oil contamination. The important factors should be optimized in order to choose a suitable method for the removal of oil contaminations. Optimal conditions for oil contamination removal by... 

One of the main environmental problems in the world particularly in Iran is the entrance of oil pollutions from petroleum waste and its related industries into the soil. There are various methods to eliminate petroleum pollutions from the environment such as physical, chemical, thermal and biological methods. In biological remediation, the environmental pollutions are eliminated by means of plants and microorganisms. Over the last two decades, ioremediation have been studied widely by experts of various fields. One of the most advantages of bioremediation comparing with the other methods is its low cost and the ability to perform at the site (in situ).In this project, we extracted two kinds... 

Every year, an enormous amount of catalysts are consumed in oil refineries during refining processes. After some regeneration cycles in order to recover their activity, they are not anymore effective and must be disposed. These spent catalysts are regarded as dangerous solid wastes as they significantly include some contaminations like vanadium, nickel, arsenic, sodium. From another point of view, the metals present in spent catalysts are highly valuable and are used extensively in steel industry and manufacture of special alloys. So, it sounds profitable to extract and recover these metals from such a cheap source instead of minerals and ores. Basically, there are two main processes, hydro-... 

Sustainable development requires the development and promotion of environmental management and a constant search for green technologies to treat a wide range of aquatic and terrestrial habitats contaminated by increasing anthropogenic activities. In this work we investigated the ability of four previously isolated fungi, BBRC 9057, BBRC 20020, BBRC 9058 and BBRC 9002, in degradation of polycyclic (PAHs) and the effect of UV irritation on fungi cell growth and degradation of PAHs. Also we studied the degradation of anthracene by thermophilic filamentous fungi in liquid and soil slurry bioreactor. Cell growth and anthracene degradation ability of BBRC 9057 increased 6.51 and 1.82 times rather... 

Due to the large portion of organic fraction of municipal solid wastes in Iran, the needing for stabilization and treatment of this waste is obvious. An appropriate method for treatment of these wastes is anaerobic digestion. By skimming through open literature which are investigated about anaerobic bioreactors, declared that despite the benefits of thermophilic bioreactors over mesophilic ones, (more destruction of pathogens, more removal of volatile solids, more production of biogas and greater resilient to organic loading rate shocks) but because of more difficulties in controlling of thermophilic bioreactors, most studies have been done in mesophilic state. This motivated us to a deeper... 

According to the environmental lows and standards, wastewater of petroleum industries such as refineries and petrochemical that include many petroleum compounds like aromatic and aliphatic hydrocarbons, must be treated up to desirable limit, before entering the collecting network. Using microorganisms is one of the fundamental ways of biodegradation of these polluted compounds. Since phenolic compounds are the main components of raw petroleum, strains that are capable of tolerating phenol and usage of this poisonous hydrocarbon are specifically important. Therefore, in this study the potentiality of the indigenous thermophilic bacterium Nocardia otitidiscaviarum strain TSH1, for degradation... 

Nowadays, because of drastically decrease of copper sulfide ore’s grade, and difficulties in leaching of them, new processes of copper production like bioleaching technique become significant. Finding the optimal conditions for bioleaching, require investing a lot of time and cost. Computer simulation is useful in this case. Temperature, affects the kinetics of dissolution reactions, type and growth rate of bacteria, and finally, rate and amount of recovery of valuable copper metal from ores, so determination of temperature within the bioheap is very important. Thermophiles are better than mesophiles in chalcopyrite bioleaching and in the range of 55 to 65 degree centigrade, thermophiles... 

The membrane bioreactor (MBR) as an alternative method for simultaneous biodegradation and separation of oily water has received more attention, recently. Normally the MBR works at ambient temperature; therefore, the yield of biodegradation recalcitrant components is low. Increasing temperature improves the efficiency of degradation and reduces the amount of produced sludge. In this study the performance of an aerobic thermophilic and mesophilic membrane bioreactor (MBR) for treating oily wastewater has been investigated. In batch conditions (without applying the membrane), a comparison between COD removal in mesophilic and thermophilic conditions was done. In thermophilic conditions COD and...