Sharif Digital Repository

The removal of ethylene glycol, one of the most widely used antifreez, with moving bed biofilm reactor (MBBR) was studied. Beside of ethylene glycol, the synthetic wastewater contained molasses and other salts as nutrient source. The packings were composed of polyethylene and shaped like small cylinders with a surface area of 500 m2 per m3 bulk volume of carriers(KMT). The COD of the feed was adjusted by varying the ratio of ethylene glycol to molasses. The total COD was 1252.5, 1345 and 1500 mg/L. The resulted showed that when the biofilm grows on the packings and its thickness is good enough, the removal efficiency increased. The increase was attributed to higher concentration of biomass... 

Removing nitrogen, as one the most surface and ground water contaminant is very important and in order to achieve this aim,nitrification and denitrification are effective and economical methods. In this work, moving bed biofilm reactor (MBBR) with initial denitrification structure, adapted from modified LUDZACK-ETTINGER (MLE) method used in order to industrial wastewater treatment with COD value in range of 900-2100 mg/lit and ammonium in range of 150-430 mg/lit in 3 hydrolic retention time of 18 , 12 and 8 hours.Aerobic reactor volume is 14.4 liter and anoxic reactor volume is 7.2 liter and reflux flow amount from aerobic reactor to anoxic reactor has considered being 3 times of anoxic... 

Discharge of Raw wastewater or effluent of Treatment plants into the natural bodies of water, in the case of high nutrients may cause serious problems such as algae bloom which results in a reduction in concentration of dissolved oxygen. Among the nutrients, phosphorous is known as a limiting factor in growth and intensification (intensifier) of eutrophication. Therefore, elimination of phosphorus from wastewater prior to the discharge point is highly important. Phosphorus can be removed chemically as well as biologically. Chemical methods are known, efficient and reliable but Problems like operational and maintenance costs and chemical sludge production cause tendency to use biological... 

There is a growing demand for efficient treatment plans which can deal with high loading of organic pollutant, considering the population growth in communities. Our country is going toward industrialization; hence, it requires more effective and efficient treatment plans as well as innovative ones. Moving Bed Biological Reactors are accounted amongst appropriate methods in removing various pollutant which has been used in recent decades. In regard to increasing demand for new treatment plans, one of the options can be upgrading of existing activated sludge systems. Two bioreactors with 10 liter volume each in parallel lines were used in this work. One of them was a regular MBBR as a blank... 

In recent years, utilization of hybrid attached and suspended growth system for modification of conventional activated sludge systems has attracted a lot of attentions. Nowadays, with development of urban areas and also introducing new emerging contaminants and as a result an increase in the influent loading of wastewater treatment facilities, the importance of upgrading and retrofitting available facilities have been highlighted. Conversion of Sequencing Batch Reactors to Sequencing Batch Biofilm Reactors is a viable solution for overcoming these problems. Eventhough several researches have been conducted on removal of different contaminants through these systems, the information about the... 

This study aims to enhance biological nitrogen and phosphorus removal performance by the innovative carbon-based moving carriers (CBMC) and reveals the role of carrier characteristics on the nutrient removal efficiency. In this research, the new carriers with the advantages of both MBBR hybrid system and physicochemical properties of activated carbon were produced based on the recycling of waste materials for the first time via a chemical-thermal process. The analysis revealed that the specific surface area of the new carrier with a rough and highly porous structure was approximately 11.4 times that of the conventional MBBR carrier. This feature plus the other physicochemical properties of... 

Quorum Sensing is a cell-to-cell communication pr°Cess depending on cell concentration. Communication among bacterial cells °Ccurs through small molecular signals called autoinducers. The consequences of quorum sensing include the activation of pathogenic properties and activation of the gene for biofilm formation. Biofilms are aggregations of bacteria that adhere to surfaces through extracellular polymeric substances. Bacteria in the biofilm phase are much more resistant to antimicrobial agents than their free-swimming counterparts (i.e. the bacteria in planktonic form). In this study, first a series of coumarin derivatives were synthesized; but due to low solubility of the synthesized... 

The use of microorganisms to remove or produce a substace is a fundamental part of biotechnology. An example is the bioreactors for phenol removal in wastewater. Biological processes are commonly done in batch reactors in which suspended cells grow in the liquid phase. The batch process needs alternate reactor washes and alternate cell cultivation, which leades to a longer time constant for for each batch. If these reactors operate in continuous conditions, the cells will leave the reactor in liquid flow, and high cell concentrations will be impossible. The biofilm layer makes a batch phase, so the liquid phase flows in and out continuously, but the cells in the biofilm layer stay in the... 

For several decades, tubular bioreactors have been used in many microbiological processes such as wastewater treatment and biopesticide production. The use of biofilm in bioreactors has positive effects on their technical characteristics, which include increasing the concentration of biomass, preventing depletion and increasing the resistance of cells against the inhibitory effect of toxic compounds. The existing mathematical models for biofilms can be divided into two general categories: analytical and numerical. In this project, the goal is to simulate the removal process of phenol by aerobic microorganisms in a tubular bioreactor with a biofilm layer on its inner wall, using numerical...