Sharif Digital Repository

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... 

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... 

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... 

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... 

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-... 

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...