فصلنامه علوم و مهندسی محیط زیست
شماره 55 (1392)

In order to prevent emission of environmental pollutants and production of elemental sulfur, the acid gas coming from oil and gas refineries is converted to elemental sulfur in the Sulfur Recovery Units (SRUs). The conversion of these pollutant gases to sulfur hardly exceeds 97% which leads to excessive sulfur dioxide sent to the flare and hence high pollution around refineries. Therefore, restricted environmental regulations should be considered. Tail gas treatment units can achieve overall efficiencies of more than 99% by eliminating the acid gases of the tail gas of SRUs. In this paper, the well-known technologies in tail gas treatment are investigated. Furthermore, the role of using a tail gas treatment unit in reducing the environmental pollutants will be investigated by means of the results achieved from Promax simulatior.

Alcohol industry is one of the industries that will lead to CH4 and CO2 emissions, because of burning sugarcane for harvesting and using of different fuels in ethanol production plant's combustion sources; in addition, there is CO2 emission during alcohol production due to fermentation of molasses. This article aimed at assessment of greenhouse gasses emissions (CH4, CO2) from one of the alcohol production unit's practice in sugarcane development company, south of Iran. Emission factors method has been used to estimate of CH4 and CO2 emission from existing emission sources in studied unit. Results revealed that total CO2 and CH4 emissions from the selected unit were equal to 81316 and 1.14 tons per year, respectively. Electrical equipments of alcohol plant and boilers are most contribution to CO2 and CH4 emissions, respectively.

Surface contaminants entering into groundwater resources, especially in arid and semi-arid regions that faced with quality and quantity restrictions on water resources, is a serious problem. Therefore, identifying vulnerable areas and driven development programs to low-risk areas is essential to achieving sustainable development in water resources management. Hence, this paper tries to zoning aquifer vulnerability to contaminant factors based on hydrological and hydrogeological features of the study area. For this aim drastic model and geographical information system has been used for processing and analysis of groundwater quality. Drastic model is used from effective characteristics in aquifer vulnerability assessment including: aquifer depth, aquifer recharge, aquifer type, soil type, slope, topography, Ingredients unsaturated zone and electrical conductivity that provided in Arcview software as 7 layers. Finally the Map of aquifer contaminant was provided according to ranking, weighting and combining layers and drastic index for the whole area was estimated at 45 to 142. The result showed that 11.75% of the study areas in South and South West are highly vulnerable and 42.99% are moderate vulnerability.

This study was conducted to identify the Macro benthos of Sisakht Kooh e Gol wetland, in two seasons (spring and autumn, 2010). Each month, in three different stations, sediment was sampled by using Van Veen Grab (0/03m2). In totally, ten groups of Macro benthos including: Gastropoda, Diptera, Copepoda, Odonata, Oligochaeta, Arachnida, coleoptera, Ephemeroptera, Hirudinea and Cladocera were identified in this survey. Shannon, Simpson, Heel and Margalof indices were calculated to consider the biodiversity of Macro benthos in the wetland and Welch Model (1992) was used to evaluate the pollution. Variance analysis results showed no significant difference. Based on the study of Macro benthos their diversity in spring was more than autumn. Sediment sampling was carried out on the based of Standard Method (1999).

The purpose of this descriptive-correlation research was to identify the role of information's sources to change the citizen's attitude toward a safety environment. The population of this study were all residents in region 14 of Tehran who had participated in flower and plant clinic classes (N=873). Total of 211 individuals were selected through a classified-random sampling. Content & face validity were assessed and confirmed by experts and specialist. In the field of environment, agricultural extension and education. Questionnaire reliability was estimated by calculating cronbach's alpha coefficient and using SPSS/win and it became 0.95. The results of Spearman correlation coefficient indicated that there is a significant relation between independent variables of age & level of education with the knowledge of citizens on healthy environment. Also the results showed that there is a significant relationship between variables of information's channels and citizen's knowledge & skill of healthy environment. Since quite many of citizens are in above age, it is recommended that through continuing education and direct influence of these activities on their behaviors, Tehran municipality provide information and knowledge of how resources to be used by citizens through multimedia and other communication tools.

Bio-environmental problems that increasingly have enfolded large spectrum of pollution, dangers and biogenesis destruction, have met local, regional and global dimensions. The major part of these problems, caused by production, change and final usage of energy and these factors directly or indirectly lead to risks such as change in continent and global warming. The main purpose of this research is checking the effect of spread of gases CO2, SO2 & NOx that are as a result of consumption of fussily fuels on Iran`s GDP and finally economical activities. For this investigation the time series Data between 1353-1385 and Cobb-Douglas pattern has been used. The effect of spread of these dopants on GDP are also reviewed by using the OLS method. The result of research show negative effect of spread of these gases on GDP. The results has also shown that 1% increase in spread of these dopants will cause to decrease of GDP in value 0.0188 percent and also 1% increase in destruction costs caused by spraed of these dopants will lead to decrease of GDP in value 0.0231 percent.

The purpose of the present study is to visual impact assessment of sandstone mines complex at Pole Doab region in Arak. For performing the assessment, Oberholzer 2005 method was employed. In order to do so, a 10-km diameter area centralizing the investigated mines complex was selected and 6 special criteria in addition to 5 other criteria, for specifying the nature of the effects, were investigated altogether, taking advantage of the pre-specified standards and map packages at Arc/Map. The results were as follows: the above-mentioned mines complex has already caused irreparable impacts on the visual resources and the landscape of this region so that all special criteria including the view of the project, the visual activities, the visual sensitivity of the landscape, and the visual recipient and disturbance are indicative of the visual effects at a very high level. Also, as a result of the dense plantation shortage in the area, the capacity of visual attraction for hiding these visual impacts is insignificant. However, the importance of visual impacts is evaluated as average compared to the social and economical developments in the area. Therefore, resuming the ongoing mining activity and future development of the two suggested new mines will be possible provided that a management program package is presented and executed and the harmful effects are diminished. Some fundamental measures of mitigating undesirable effects have pointing out in brief.