فصلنامه محیط شناسی
سال سی و پنجم شماره 2 (پیاپی 50، تابستان 1388)

Structure and function of socio – economic systems present different spatial effects in different countries of the world. In this study, structure and function of social and economical systems is analyzed to identify of changes within urban spatial structure. In Tehran, effects of political and economic factor is analyzed for identification of changes of its spatial structure and its periphery in The past years. The most important criterion of rantier government is getting income from rant more than 42% while in Iran government income driven from The export of raw materials (including crude oil)has exceeded this figure. Therefore The nature of Iranian economy of oil – based and its related income. The spatial structure of Tehran metropolitan area is heavily affected by this rantier system, since 1970s. During 1970s, Tehran, politically and economically, transformed from an ordinary Asian capital to an international important city. In this condition, the Palavi regime intervened directly as its political centre. At this time, Tehran was become a complete pattern of a twofold structure. Also taking into consideration all the intermediate grades the city and urban was developed. This made the northern and southern parts in front of each other and created the growing social contracts.

With the publication of the Brundtland Report carried the sustainability discussion into governments and businesses worldwide, much effort has gone into clarifying the meaning of the sustainability concept. To make the concept measurable and applied city sustainable idea, some new method was needed. So the method named ecological footprint has been presented.The ecological footprint method that developed by professor William Rees and D.r Mathis Wackernagel in the early 1990s. Accounting index that translates human resource demand to the land area required to produce the resources needed and sequester of CO2 or dispose of wastes. In this context, Rees and Wackernagel simply defined sustainability as living peacefully in relate comfort and with nature. The ecological footprint was originally conceived as a simple and elegant method for comparing the sustainability of resource use among different populations. It is now a widely consider as the indicator of sustainable development. Ecological Footprinting translates resource consumption into the land area required to sustain it, and allows for an average per capita Ecological footprint for a region or nation to be compared with the global average. Finally the consumption of these populations is converted into a single index called the land area. This area is then compared to the actual area of productive land that the given population inhabits, and the degree of unsustainability is calculated as the difference between available and required land. Unsustainable populations are simply populations with a higher ecological footprint than available land. It was also proposed that ecological footprints could be used for policies future of design and planning. Ecological footprints calculated according to this original method became important educational and planning tools in highlighting the unsustainability of global consumption.

Today as the land-filling of solid wastes without taking into consideration the environmental issues would threaten the land greatly, the selection of an appropriate site for hygiene disposal of the wastes is a necessity. Analytic Hierarchy Process (AHP) is one of the most frequently used methods of multiple criteria choices. In site selection of an optimum place fro landfill in the city of Bonab located in East Azerbaijan Province, the AHP model has been used in the context of the software called Expert Choice. After the determination of AHP layers including goals, criteria, and the choices (landfill sites) a couple and paired comparison has been accomplished among the whole sample with the purpose of weighing all variables. Alongside the weighing for the samples, a comparison was done between the judgments that should not exceed 0.1%. The resulting findings were plotted in graphs. Among all 9 environmentally approved sites for landfilling in the study area, site No. 4 was selected as the preeminent landfill site.

Forest ecosystems that have spent a long time to mature, offer important goods and services to humanity. Hence, utilization and exploitation of these resources should be based on careful assessment of their ecological value and potential. Ecological land evaluation is an approach based on land quality, vulnerability and potential assessment for different acceptable uses drawing upon related models. We used a geographical information system to prepare a data base including physiography and topography, elevation, slope, pedology, lithology, rainfall and temperature, forest density, tree growth and values for forest evaluation. The data base was clipped for the Dohezar and Sehezar watersheds in the north of Iran. Using seven descriptive models of forest capability in Iran through a systematic land evaluation, we determined forest potential based on the Boolean logic and Boolean raster layers of the prepared data base. Multiplication of the Boolean raster layers or constraints resulted in the recognition of classes 1 to 5 of the models whereas no class 6 and 7 were distinguished. Of the first 5 classes of the forest capability, class 3 had the highest share in terms of the areal coverage.

According to performed classification by Ramsar convention (1971), Choghakhor is one of the most valuable wetlands of Iran. Despite of high abilities of perspective and variation of habitats, tourism valuations are not considered. In this study, promenade valuation Choghakhor wetland was estimated by using Zonal travel cost method. These methods is based on using map, sight, social-economical characteristics of visitors and also increase in cost and distant to area. Therefore by considering the wetland as the centre, 9 concentric circles with constant distances of 150 km were drawn around it which covers the whole country. After that population in each area was calculated by using existing map and statistics. In the next step by using completed questionnaire by viewers, social and economical data were derived and analyzed. According to existing data relation between travel cost and number of visitors was concluded. Then new number of visitors regarding to increasing costs was calculated by considering various inputs and adding them to total amount of available costs and request curve of wetland was drawn. Calculations showed that Choghakhor wetland has high promenade-economic value. Money making value depends on best natural location and beautiful sight around it. Concluded results from this study provided some valuable information to reach protection and graduation goals level of promenade of wetland without any harm to its ecosystem.

Green space is counted as one of the important bases of each city, especially great cities like Tehran. With considering to vast application of urban Green Aria, the necessity of the managing these sources is felt more day-by-day. For proper managing each source, first the inventory of that source is taken into the consideration. Regretfully so far there has been no comprehensive studios pattern for studying the situation of urban forests and urban green area.In this study, by using of describing aerial photos as numerical, the urban green aria has been classified. After performed survays, it was certified that classification on numerical ortho photo mosaics is easier and more precise, comparing with manual description, and consequently this method was used. The method was in a way that at the first step, 23 pieces of aerial photos 1:800 and 1:10000 of year 1381 in District 6 of Tehran were orthofied by using PCI Geomatica software and then a mosaic of orthofied photos was prepared. In the next step, classifying on 5 classes was done on numerical ortho photo mosaic and the map was prepared because of this classification by using Arc Gis software. In addition, the surface and the length of the levels were calculated. These levels were as urban park in scale of fore arial and arial, urban park in scale of locality, tree complexes, linear trees and scattered trees.For calculating cover crown, dotted net with the distances of 1 millimeter (as numerical layer) was used and for creating a relationship between this element(cover crown), separately collecting statistics on the photo and in the field, sampling with the sample parts having a fixed surface (7 Ares) and 5-trees-transects were done.

Sulfur utilizing autotrophic denitrification synthetic wastewater in up flow packed --bed reactor was evaluated under different concentrations of alkalinity and organic matter. The reactor was filled with granular elemental sulfur particles with diameters of 2.8-5.6 mm and porosity of 40%. The initial culture was prepared from sludge of Shahrak Ghods wastewater treatment plant. First, the stoichiometry ratios,? SO4/?NO3-N (sulfate produced to nitrogen nitrate removed) and? ALK. /?NO3-N (alkalinity consumed to nitrogen nitrate removed) were determined 7.05 and 2.92 mg/mg respectively by varying the influent nitrate concentration. Under sufficient alkalinity, complete nitrate removal occurred with 650 mg NO3-N/lit influent nitrate concentration and 0.792 Kg NO3-N/(m3-day) volumetric loading rate. As influent alkalinity decreased to values less than stoichiometry requirements, the nitrate removal efficiency decreased to a final percentage of 60.2% at 810 mg/lit alkalinity as CACO3. Under this condition, organic matter (methanol) was added to feed at concentrations of 247, 494 and 741 mg/lit, equivalent to 20%, 40% and 60% of stoichiometry requirements for heterotrophic denitrification. Results showed that by increasing the methanol concentration, the above stoichiometry ratios decreased to a final ratio of 2.66 and 0. 04 respectively and the overall nitrate efficiency increased up to 100%. Increasing effluent pH and turbidity (as an indirect determinant of effluent biological mass) and almost complete removal of influent methanol was also observed. All these changes imply the co-occurrence simultaneous sulfur based autotrophic and heterotrophic denitrification in bio reactor and show that the addition of controlled concentrations of organic matter to high nitrate wastewater with insufficient alkalinity not only compensates for the lack of alkalinity but also improves the performance of sulfur utilizing autotrophic denitrification

During recent years oil products has decreased because of growing population and increasing demand to oil products and decreasing of crude oil extraction at compare to export. However, to achieve suitable levels of production, the use of improved technologies should be considered. Another way to prevent the evaporation and leakage from oil storage tanks and their products are using of storage tanks. Storage tank of hydrocarbons are important evaporation source of volatile organic compounds.In the present investigation the methods of hydrocarbon evaporation calculation is studied. Subsequently hydrocarbon evaporation is computed from Tehran's North-West storage tanks using Tank-4 software. All necessary parameters which influence evaporation from storage tanks are introduced into the software. Estimation of the evaporation rate of oil products from storage tanks requires comprehensive information. The Required data has been provided from National Iranian Oil Product Company. Tehran's North-West storage tanks is located in Shahran region and provide oil products of west of Tehran. There are 11 tanks, including five fixed roof and six floating roof tanks. The tanks are contained Gas oil, Gasoline and Kerosene. Ten tanks are active and one of them is under overhaul. The cylindrical tanks are with diameter of 44 meters and height of 14.64 meters. This software is designed to estimate evaporation from organic liquid storage tanks and need to specific information about tank (dimensions, construction conditions and color. ..), type of liquid (chemical components and liquid temperature. ..) and position of the tank (nearest city, temperature and. ..) to present the evaporation from these tanks to the air. Final report is included monthly and annual emission for each chemical material or combination of chemicals is stored in the tank. Evaporation rate is considered from three tanks with number one, five and six, respectively containing gas oil, gasoline and kerosene.

The main objective of the research is to study noise pollution in Khorram Abad, presenting executive strategies to control or reduce it. Therefore, 38 stations were selected at the region to measure the noise level round-the-clock, and the samples were also taken for a week in the middle of spring and summer, 2007. The measurements were carried out during the day (7:00 AM to 10:00 PM) and night (10:00 PM to 7:00 AM). The measured noise parameters in the sampling stations were Lmin, Lmax, Leq, and Spl, and then also calculated using the formulas TNI, LN (L1, L10, L50, and L90), Ldn. The noise average equal levels obtained at the sampling stations were compared with the standard ones in Iran. At all stations, such values were more than the national standards. Moreover, 500 questionnaires (250 in spring and 250 in summer) were analyzed to study the resident's level of awareness and discontentment when facing noise pollution. Statistical analyses of the questionnaires showed a significant relationship between the men variable and nervousness, also between the women variable and the headache caused by traffic noises (in both seasons). The measured noise parameters in both spring and summer, also during days and nights in both seasons separately were statistically analyzed. The sampling stations at the three districts of the municipality were also analyzed regarding the parameters mentioned. Among the main results obtained by the research was providing noise alignment maps for the parameters Spl, Leq, Lmax, Ldn (for days and nights separately) in both spring and summer, on which the critical regions concerning noise pollution were identified. Then, due to the results obtained from the measurements and their comparing with standard values, and also regarding ways in other countries, suitable strategies were developed.

Moisture and air pollutions intensify metallic and nonmetallic surface corrosions. Corroded surfaces exposed to rain washing cause pollution transportation in water and soil environment, especially in industrial areas. Investigation of storm runoff quality in Pars Special Economic Energy Zone (PSEEZ) has shown heavy metals in storm basins of gas refineries and petrochemical industries.In this paper, atmospheric corrosion in PSEEZ gas and petrochemical industries was investigated to determine metallic pollution sources. Considering the geographical location of industry, the topography, and prevailing winds, the location of four air monitoring stations were determined. Then, major air pollutants like sulfur dioxide, sulfatation rate, and chloride deposition as well as relative humidity were investigated in all four stations. Annual average concentrations of Zn, Cu, and Al showed that at present the severity of atmospheric corrosion in 62.5% of the time is moderate, in 33.3% is moderate to high, and in 4.2% is in the range of corrosive and very corrosive. Furthermore, based on annual averages, the severity of atmospheric corrosion for carbon steel was classified as very corrosive.

Sulfuric acid production plants are one of the main sources of sulfur oxides, emission to the atmosphere. In the present study to control sulfur oxides of Sulfuric acid plant two methods have been selected. The first method is desulfurization by ammoniac (Plant A) and the second one is a combination of the first method and dry scrubbing process with calcium hydroxide as the absorbent material) Plant B). Concerning economical investigation two techniques were carried out regarding the conclusion of the simulation. Considering the simulation results by HYSYS v3.1 software, 110 tones of sulfur oxides production were eliminated daily in two methods. As elimination of sulfur oxides was nearly the same (110 tones daily) in both methods, the external costs of production reduction of SOX as a pollutant substance is the same, too. Therefore, economic index of these two methods were calculated through COMFAR? software with two presuppositions i.e. considering the external costs and not considering the external costs, the internal rate of return (IRR) in the first method was about 46% which is more than that of the second method (18%). Moreover, the payback period in the first method was 3 years which is less than that of the second method (5 years). Net present value (NPV) as a major criterion in economics was calculated, too. In the first method NPV was more than that of the second method which is a sign of an appropriate flow of cash in the first method. In cash flow of implementation of the second presupposition, there would be 541286 million rials save as the result of reduction of external costs. Consequently, the first method has economic priority over the second method for desulfurization of sulfuric acid production plants.

Transport of pathogenic bacteria has been recently considered a major source surface and subsurface water contaminations. Soil could affect transport or filtering of bacteria depending on its physical and chemical properties. Calcium carbonate and calcium sulfate are two important minerals of arid and semi-arid soils that their effect on bacteria transport has not been investigated, yet. In this study, the influences of calcium carbonate (0, 5, 10 and 20 %w/w) and calcium sulfate (0, 5 and 10 % w/w) in sand mixtures on Pseudomonas fluorescens transport were studied under unsaturated condition the experiment was in factorial arrangement adapted to a completely randomized design with three replicates. The mixtures were poured into pyrex cylinders with length of 20 cm and diameter of 7 cm and a steady unsaturated flow was established. Then, bacteria suspensions of 106 cfu cm-3 were applied as step input on the columns. The effluent concentration was measured during leaching up to 5 pore volumes (PV). The calcium carbonate and calcium sulfate could significantly affect the effluent concentration. The highest and lowest amounts of bacteria transfer were recorded for sand and 20% calcium carbonate treatments, respectively. Calcium carbonate application significantly reduced the effluent concentration. The effect was significant for 0.25 PV, 0.5 PV, 1 PV, 2.5PV and 5 PV. However, the influence of calcium sulfate was not significant in all of the effluent volumes. Breakthrough curves obviously demonstrated the filtering and adsorption of bacteria when calcium carbonate and calcium sulfate and carbonate minerals which might be used to reduce the bacteria transport and/or subsurface water contamination.

This document provides feasibility study of using treated domestic wastewater in concrete mixing. Today, concrete is one of the most important construction materials. From first time that concert was used in construction materials, always the drinkable water used for concrete mixing water. Domestic wastewater contains about 400 ppm of organic materials. After the treatment of wastewater, concentration of organic matters will reduce to 20 ppm which is so low for affecting strength of concrete. Treated wastewater from SHAHRAKE GHODSE wastewater treatment unit was used in the experiments. Before using treated wastewater as the mixing water, it was analyzed in laboratory. Then the results were compared with US standards and UK standards. The sample was made of 3 main unit streams, primary sedimentation unit; secondary sedimentation unit and final outlet treated wastewater. Then the sample analysis was done by the Faculty of Environment in Tehran University. Based on the standards, for a standard block, when the reduction in strength of the sample is less than ten percent, the treatment of wastewater is suitable for using as the mixing water of concrete. In the situation of using enforcement concrete the block should cover with suitable materials to avoid cored of bar in concrete.