دانشگاه تهرانJournal of Environmental Studies1025-862020019980121--14451FAJournal Article19700101دانشگاه تهرانJournal of Environmental Studies1025-862020019980121--14452FAJournal Article19700101As a result of Progress towards industrialization in the country, the volume of industrial wastewaters is gradually increasing and it is estimated to reach 1 to 1.5 billion cubic meters in 2007. With respect to great volume and pollution of these wastewaters, the necessity for their treatment looks obvious. Biological Treatment is a cost - effective solution of industrial wastewater management problems. Many factors affect process selection for biological treatment, but raw wastewater characteristics and the treatment objectives are the most important for The process selection for
biological treatment of industrial wastewaters. In this study, some of the considerations for selecting biological treatment processes for industrial wastewaters have been discussed. A simplified diagram summarizing these considerations is presented, and it is believed that the diagram developed herein could help the practicing engineer in arriving at a rational process selection for any particular case.As a result of Progress towards industrialization in the country, the volume of industrial wastewaters is gradually increasing and it is estimated to reach 1 to 1.5 billion cubic meters in 2007. With respect to great volume and pollution of these wastewaters, the necessity for their treatment looks obvious. Biological Treatment is a cost - effective solution of industrial wastewater management problems. Many factors affect process selection for biological treatment, but raw wastewater characteristics and the treatment objectives are the most important for The process selection for
biological treatment of industrial wastewaters. In this study, some of the considerations for selecting biological treatment processes for industrial wastewaters have been discussed. A simplified diagram summarizing these considerations is presented, and it is believed that the diagram developed herein could help the practicing engineer in arriving at a rational process selection for any particular case.دانشگاه تهرانJournal of Environmental Studies1025-862020019980121--14453FAJournal Article19700101Lead is one of the important pollutants in our industrial society. The toxic effects has been extensively studied by different stand point of views; such as inhibitory pathway enzymes in hemoglobin biosynthesis that also disturbes the nevous systems. In the present study, the thermodynarnic aspect of Human Serium Albumin (HSA) destabilization by lead, has been studied with various experimental techniques sutCh as equilibrium dialysis, thermal denaturation and titration spectrophotometer at pH 3.2 and different temperatures. The number of binding sites, the strength of binding and the magnitude of binding cooperativity of lead to HSA were determined at two temperatures of 27°C and 37°C. The binding process is endothermic. So, heat increases the toxic effect of lead. Moreover, the melting temperature of protein, as a thermodynamic stability parameter, is decreased by increasing environmertal concentration of leadLead is one of the important pollutants in our industrial society. The toxic effects has been extensively studied by different stand point of views; such as inhibitory pathway enzymes in hemoglobin biosynthesis that also disturbes the nevous systems. In the present study, the thermodynarnic aspect of Human Serium Albumin (HSA) destabilization by lead, has been studied with various experimental techniques sutCh as equilibrium dialysis, thermal denaturation and titration spectrophotometer at pH 3.2 and different temperatures. The number of binding sites, the strength of binding and the magnitude of binding cooperativity of lead to HSA were determined at two temperatures of 27°C and 37°C. The binding process is endothermic. So, heat increases the toxic effect of lead. Moreover, the melting temperature of protein, as a thermodynamic stability parameter, is decreased by increasing environmertal concentration of leadدانشگاه تهرانJournal of Environmental Studies1025-862020019980121--14454FAJournal Article19700101دانشگاه تهرانJournal of Environmental Studies1025-862020019980121--14455FAJournal Article19700101دانشگاه تهرانJournal of Environmental Studies1025-862020019980121--14456FAJournal Article19700101The main part of the atmospheric boundary layer is the mixed layer, in which air pollution is uniformly dispersed. In this work, the mechanisms involved in the growth of the mixed layer is first discussed and a turbulence model is presented for its growth. The results of this model is used in an integral model for air pollution prediction in an urban area. Using a correct model with proper adjustments, one can predict the air pollution concentration for various urban areas with different conditions, with some accuracy. From the comparison of-the results, with actual measurements, obtained for two typical summer and winter days, it is clear that the model can correctly predict the daily variation of pollution concentrations. Typical winter concentrations are higher than for the summer ones. For cities like Tehran, topography and air stability, can limit the air flow, and hence, can cause substantial increase in air pollution concentrationsThe main part of the atmospheric boundary layer is the mixed layer, in which air pollution is uniformly dispersed. In this work, the mechanisms involved in the growth of the mixed layer is first discussed and a turbulence model is presented for its growth. The results of this model is used in an integral model for air pollution prediction in an urban area. Using a correct model with proper adjustments, one can predict the air pollution concentration for various urban areas with different conditions, with some accuracy. From the comparison of-the results, with actual measurements, obtained for two typical summer and winter days, it is clear that the model can correctly predict the daily variation of pollution concentrations. Typical winter concentrations are higher than for the summer ones. For cities like Tehran, topography and air stability, can limit the air flow, and hence, can cause substantial increase in air pollution concentrationsدانشگاه تهرانJournal of Environmental Studies1025-862020019980121--14457FAJournal Article19700101دانشگاه تهرانJournal of Environmental Studies1025-862020019980121--14458FAJournal Article19700101دانشگاه تهرانJournal of Environmental Studies1025-862020019980121--14459FAJournal Article19700101The problem facing the nations for the cleanup of hazardous waste sites are significantly greater than that anticipated two decades ago. The use and manipulation of microorganisms for treatment of municipal wastewater has been applied since ancient times. The use of microbes to degrade waste is as old as nature, and man has used bioremdiation techniques for decades to degrade municipal wastewater, refinary waste, and specific chemial process waste streams. In the last decade significant advances have
been made in aquiring knowlege about microbial metabolism of xenobiotic compounds.. Bioremcdiation is the process of removing or reducing the mobility and or toxicity of contaminants of concern at a site. Bioremediation is a managed, demonstrated active treatment process that uses micro organinSIT1S to degrade and transform organic chemicals in contaminated soil, sludges, and resid ues. Groundwater con tamina tion may be reduced or completely eleminated by this technology. Bioremediation is becoming a popular approach in the cleanup of petroleum hydrocarbons, because it is simple to maintain, applicable to a large area, cost - effective, and most importantly, it leads to the complete dsetruction of the contaminant. Microbial degradation of hydrocarbons results in the release of innocuous products such as carbon dioxide, water, and cellular biomass as the final products. Bioremediation processes have resulted from the application of knowledge from microbiolgy, biochemistry, environmen tal engineering and chemical engineering. Bioremediation however, is not the answere to all contamination problems. Its applicability must be determined at each site which would be dependent on the local site microbology, hydrology, geology and chemistry.
In this aricle other means of treating the contaminated sites are listed and compared with bioremediation. Finally, two case studies
regarding Exxon Valdez oil spill and Persian Gulf spill are discussed.The problem facing the nations for the cleanup of hazardous waste sites are significantly greater than that anticipated two decades ago. The use and manipulation of microorganisms for treatment of municipal wastewater has been applied since ancient times. The use of microbes to degrade waste is as old as nature, and man has used bioremdiation techniques for decades to degrade municipal wastewater, refinary waste, and specific chemial process waste streams. In the last decade significant advances have
been made in aquiring knowlege about microbial metabolism of xenobiotic compounds.. Bioremcdiation is the process of removing or reducing the mobility and or toxicity of contaminants of concern at a site. Bioremediation is a managed, demonstrated active treatment process that uses micro organinSIT1S to degrade and transform organic chemicals in contaminated soil, sludges, and resid ues. Groundwater con tamina tion may be reduced or completely eleminated by this technology. Bioremediation is becoming a popular approach in the cleanup of petroleum hydrocarbons, because it is simple to maintain, applicable to a large area, cost - effective, and most importantly, it leads to the complete dsetruction of the contaminant. Microbial degradation of hydrocarbons results in the release of innocuous products such as carbon dioxide, water, and cellular biomass as the final products. Bioremediation processes have resulted from the application of knowledge from microbiolgy, biochemistry, environmen tal engineering and chemical engineering. Bioremediation however, is not the answere to all contamination problems. Its applicability must be determined at each site which would be dependent on the local site microbology, hydrology, geology and chemistry.
In this aricle other means of treating the contaminated sites are listed and compared with bioremediation. Finally, two case studies
regarding Exxon Valdez oil spill and Persian Gulf spill are discussed.دانشگاه تهرانJournal of Environmental Studies1025-862020019980121--14460FAJournal Article19700101This paper is ocncerned with introducing different economic methods for evaluating the environment. Apart from making familiar those people who are interested in environmental issues, the main aim of the paper is to remind that we should not any more think of the environment as a free and valueless good. The planners and policy makers should recognise that the environment has a latent economic value, which is indeed very high under the present circumstances. The methods being introduced in this paper are either related to (market prices - such as opportunity cost method), and (surrogate markets - like hedonic pricing method), or based on (interviews and questionnaires - e. g. contingent valuation method). In addtion to presenting practical applications, the weaknesses of these methods are also being highlightedThis paper is ocncerned with introducing different economic methods for evaluating the environment. Apart from making familiar those people who are interested in environmental issues, the main aim of the paper is to remind that we should not any more think of the environment as a free and valueless good. The planners and policy makers should recognise that the environment has a latent economic value, which is indeed very high under the present circumstances. The methods being introduced in this paper are either related to (market prices - such as opportunity cost method), and (surrogate markets - like hedonic pricing method), or based on (interviews and questionnaires - e. g. contingent valuation method). In addtion to presenting practical applications, the weaknesses of these methods are also being highlightedدانشگاه تهرانJournal of Environmental Studies1025-862020019980121--14461FAJournal Article19700101--