فصلنامه پژوهش در بهداشت محیط
سال چهارم شماره 3 (پاییز 1397)

Background and Purpose: In recent years, the use of Bus Rapid Transit in Tehran has been taken into consideration and largely follows the satisfaction of the citizens of Tehran. Bus Rapid Transit (BRT) system reduce transport costs, increase speed and, ultimately, the comfort of the public. Therefore, in this research, the impact of the performance of BRT system is discussed. In order to achieve this goal, first, the traffic volume of vehicles in two scenarios by existence and nonexistence of BRT were obtained by the model; Eventually, after calculating the driving pattern by measuring in the field, estimating the fuel quality and calculating the type of fleet of the path, the amount of emissions of pollutants produced by each vehicle were obtained based on the model International Vehicle Emissions (IVE); and Eventually, the pollutants emissions from moving sources were compared in these two scenarios to achieve the effectiveness of the using BRT system. According to the results obtained from the route, the existence of BRT reduced carbon monoxide by 134.92 kg, volatile organic compounds by 5.13 kg, benzene by 0.48 kg, carbon dioxide by 4631.97 kg, nitric oxide by 0.37 kg and methane emissions by 6.86 kilograms. But it increased particles of less than 10 microns by 0.48 kg, nitrogen oxide by 0.8 kg and sulfur oxide emissions by 0.97 kg. According to the obtained results, the driving pattern and the traffic volume are two important variables in the IVE. The emissions of carbon monoxide and contaminants of volatile organic compounds are released majority from light cars. At the end, the presence of BRT leads to a significant reduction in carbon dioxide emissions, which is the main source of greenhouse gas emissions.

Background and amain: The most important global environmental problem, especially in large cities, is air pollution. This is regarded as a serious threat to human, society and environment health. This paper aims to investigate the physical factors of stack affecting the concentrations of the pollutants through the AERMOD model. In this research, modeling was carried out for four factories Orchin, Khayyam, Noavaran and Meybod Tile Company during the first six months of 2015. The study area comprised 20 × 20 km2., being centered on the Khayyam factory. Meybod meteorological data were used in the form of a three-hour mean status to perform the sub-model of AERMET. A Digital Elevation Model (DEM; SRTM 50 m) was used to perform the sub-model of AERMAP. In order to conduct the statistical analyses, the SPSS software program (Version 22) was used. The results of the statistical analyses showed that the abovementioned factories had significant differences in terms of dispersion of particles: The Noavaran Factory and Meybod Tile Company had the maximum and minimum concentrations respectively. Finally, the model was verified by measuring 23 points in different months with an environmental device. According to the obtained results, the correlation results, the results of the model, and the samples areas were confirmed with P-value=0.002. According to the results of Freidman ranking, the physical factors of the factories affecting the concentration of the particles in order of priority were the stack diameter, the exit rate of suspended particles, the exit speed of the particles, the height of the stack, the temperature of the stack, and the receiver’s height.

Constructed wetlands and conventional treatment methods have a same duty in wastewater treatment، but they have different methods and mechanisms. The aim of this study was to investigate the removal of phenol from synthetic wastewater using horizontal sub-surface flow constructed wetland and the aeration and hydraulic retention time effects on phenol removal efficiency. This study was an interventional study that was carried out on a laboratory scale in horizontal sub-surface flow constructed wetland. In order to determine the effect of aeration on the efficiency of phenol removal, ، one reactor was aerated and another one was non-aerated. Pumice was used as a media. The wetlands were planted by Phragmatis australis. The results showed that phenol degradation in both aerated and non-aerated wetland was influenced by organic loading rate and hydraulic retention time. It was also found that the removal of phenol was completely accomplished in both aerated and non-aerated wetlands. This is while the phenol removal rate is higher in aerated wetland, ، and in order to achieve the same results, ، the hydraulic retention time in non-aerated reactor should be about twice as high as the aerated one.  Horizontal sub-surface flow constructed wetland has a high efficiency in phenol removal. Therefore, if the conditions of operation especially hydraulic retention time are optimized، it can be applied as an effective system for phenol removal from wastewater.

The solid waste in landfill is transformed into landfill gas during a biochemical conversion process called bio-degradation. Landfill gas is a product of waste decomposition containing 40 to 60 percent of methane and various amounts of other gases. The present project aims to estimate the proportion of environmental gases of Landfill No. 1 in Shahin Shahr (total landfill gas, methane gas and carbon dioxide gas), compare gas emissions over a 30 year period, and assess the capacity of the landfill for energy extraction. Material and Methods: The field of research was Landfill No. 1 at Shahin Shahr Recycling Plant (Isfahan) located in Ja’farabad Mountains, whose capacity was completed in 2010 and landfill gas assessment was carried out. The total amount of produced gases including methane and carbon dioxide was calculated using the first-order degradation model over a 30 year period. The proportions of these gases in Landfill were calculated from 2013 to 2043. The results show that the amount of landfill gases production declined over the time. The maximum production of methane and carbon dioxide was about 350 and 950 thousand kilograms in 2013 and the minimum production of methane and carbon dioxide is estimated about 57 and 157 thousand kilograms, respectively, in 2043. The total volume of gases produced in this landfill has been estimated to be about 15 million cubic meters in 30 years, of which 27 percent is methane and 73 percent is carbon dioxide. The amount of methane and carbon dioxide gas is estimated to be about 5 million and 13 million kilograms in 30 years, respectivel. Generally, the landfill gases production declined over the time. It is recommended to use energy recovery technologies for controlling greenhouse gas emissions and generation of required energy for the ShahinShahr recycling plant in order to use this volume of gas.

Background and purpose: More than 85 percent of urban sewage and a large proportion of industrial wastewater are water, so refined sewage can be used in any part of the activities that require water. The aim of this study was to provide a practical solution for quantitative and qualitative groundwater aquifer regeneration in areas where soil and groundwater conditions are suitable for artificial nutrition by introducing refined sewage to groundwater aquifers with a lower quality. In this study, the chemical quality criteria for artificial feeding of aquifer including hydraulic conductivity, thickness unsaturated soil, topography and land use in geographic information systems were studied to determine the appropriate public areas for artificial feeding in land aquifer Birjand. Also, the criteria for increasing the improvement of chemical quality (quantitative and qualitative increase) were also weighed using the (Analytic Network Process) ANP method and Super Decisions software, so that the chemical quality of the aquifer was ranked as the first priority of the artificial nutrition. Based on the nutritional goal, 6.63 square kilometers of land were classified in very good and 50.66 square kilometers in good regional classifications. Based on the objective of improving the chemical quality , 1.13 square kilometers of lands were classified into a very good category and 55.61 square kilometers in good classification. For this purpose, the treated wastewater is injected into areas of an aquifer that has poor quality, to improve its quality. In this research, using the location of susceptible artificial feeding areas, a solution was proposed that, while feeding areas of an aquifer that has poor quality, also increases its quality. This will make aquifer water suitable for agricultural use. This solution preserves higher quality resources for drinking and sanitary purposes.

Since, the treated effluents can be used as a reliable and sustainable source for agricultural activities, the treatment and recycling of wastewater is the most important solution in the arid and semi-arid regions of the world, such as Iran. a In Iran, the reuse of treated wastewater is becoming a validated method to recycle useful ingredients of the wastewater to the water cycle. Therefore, the present study was conducted to determine the quality of Torbat-Heydarieh's municipal wastewater treatment plant effluent for irrigation and agricultural uses. In this study, the chemical and microbiological analysis of Torbat-Heydarieh's municipal sewage treatment plant effluent has been investigated for agricultural uses in the mentioned method in 2015 year. The considered output parameters of the wastewater were (Total Suspended Solid)TSS, Biochemical Oxygen Demand (BOD5), COD, Coliform, nitrate, Turbidity parameter, sulfate, phosphate, chloride and poisonous non-organic compounds. Data analysis was performed using DSTAT software and statistical volume of 45 samples. Findings: The results of the chemical analysis of municipal sewage showed that the amount of nitrate in the wastewater is higher than the standards of World Organization Health (WHO) and (Food and agriculture Organization) FAO. Therefore, appropriate strategies should be considered for agricultural applications. The results of the chemical analysis of municipal sewage showed that total TDS, dissolved Oxygen, BOD, COD, caloric, magnesium, sodium and calcium, phosphate and chloride in sewage treatment plant are in standard range.

This analytical descriptive study was conducted to evaluate the carbon emissions from the use of fossil fuels for gasoline, petroleum gas, petroleum fuels and kerosene during the period of 1306 to 1394 in 1397. The amount of fossil fuel consumption in the period from 1306 to 1394 was collected using the statistics of consumption of petroleum products, which was published by the Public Relations Publications Office of the National Iranian Oil Products Distribution Company. The total consumption of petroleum products in the period between 1306 and 1394 shows that there was a positive growth, so that in 1394 it was consumed by 73.1 billion L. The amount of carbon emissions from gasoline consumption in the year 1306 and 1394 was 9234500 and 59607018500 kg of carbon dioxide per year, respectively. The consumption of gas, kerosene and kerosene has grown steadily over the years and the consumption of these fossil fuels has increased. The analysis of the results shows that gasoline consumption has increased. Gasoline is one of the most consumed fossil fuels in Iran, which is mainly used in light car transport. Of course, it should be noted that the Iranian population has grown positively since the last 40 years.