JOURNAL OF ENVIRONMENTAL SCIENCE AND TECHNOLOGY
Year:2006 | Volume:8 | Issue:2 (29)|Papers Count:13

In urban areas, overpopulation has turned many agricultural lands into residential, commercial and industrial ones. These changes have had such undesirable effects on urban environment as a decrease in vegetation and an increase in temperature. Therefore, it is necessary to evaluate the effects of land use changes for the proper management of urban areas. Remote sensing technique can provide good information about land use changes in a short time. It can also be used to study the past changes in land use to predict the future changes. The main objective of this study was to develop a methodology for monitoring land use changes in urban areas using satellite data and remote sensing technique. In a case study, four cities in the province of Yazd, Iran, were selected. To map temporal changes of urban vegetation, Normalized Difference Vegetation Index (NDVI) were derived using Land sat ETM+ data bands (1990 and 2002). Then, the NDVI values were classified into six groups to study the quality of these changes in the above-mentioned periods.The results of this study indicate spatio-temporal changes of urban vegetation in the last decade.

According to scientific studies, vehicles contribute to almost 70 percent of emitted pollutants, which is mainly due to the consumption of fossil fuels. Considering the problems of air pollution and the environmental consequences caused by such fuels as gas-oil and petrol consumed by public and private vehicles, the number one priority of certain countries including Iran is to substitute these fuels with natural gas because of the least amount of pollutants it produces. Therefore, it is necessary to conduct studies aimed at optimizing the technology of gas-driven vehicles. In this research, the effect of turbochargers on the emitted pollutants and fuel consumption of gas-driven buses model 355 (one of CNG buses of Tehran public transportation Vahed Company) was determined, using laboratory data and statistical analyses. In this study, first the appropriate power was considered with regard to the types of turbochargers installed on the CNG buses model 355, and then the amounts of pollutants for each type were measured using the thermodynamic principles and baseline figures. After that, these amounts were compared with the Euro-2 standard pollution rates.Finally, the turbocharger that could meet the Euro-2 standards was selected, i. e., Garrett model GT37.

The present investigation deals with the quality of capacity building and institutional strengthening of strategic environmental assessment (SEA) in the industrial field as well as determining the environmental strategies for industrial sustainable development in Iran. The main goal of this study is to systematize the environmental considerations in industrial development strategies, policies, plans, and programs at the highest strategic decision- making levels and to ensure environmental considerations and alternatives together with other economic and social considerations. To analyze Iran's industrial development strategies, the matrix method SWOT(strengths, weaknesses, opportunities and threats) was used as one of the most practical techniques of strategic programming. The results of SWOT matrix analysis are indicative of the degree of need for performing an SEA in connection with the country's various industrial strategies in a categorizing priorities system. Among all industrial strategic policies, 2 strategies have been screened and evaluated as the first and 4 strategies as the second priorities. The industrial strategies with the first priority require suitable capacity building for the formation of developing specialized mother companies for the non-governmental sector's development in the industrial field and interaction with foreign companies to enter the international markets and to absorb direct foreign investment. Industrial strategies requiring SEA in the second priority include supporting and encouraging strategies for the industrial exports, providing aid and improvement for the institutions that support small-and medium-sized industries, creating infrastructures for joining the WTO, and decreasing the governmental supervision and restriction in the industrial field. Based of the results of this study, the achievement and realization of the conditions for environmental quality sustainability and industrial development sustainability in Iran call for large-scale strategic decision-making and policy-making regarding the above-mentioned strategies in the framework of SEA methodology and in the pre-research phase (policies, plans and programs) as well as performing EIA projects.

The aim of this project is to study the wastewater treatment system of Sahand dairy products factory and to provide a solution for the problem. The existing wastewater treatment system in this factory is an anaerobic and aerobic system, where the aerobic system is an extended activated sludge. This study had two phases as follows: Phase One: This phase lasted from February 1, 2003 to September 1, 2004. Based on the integrated sampling, the company's wastewater was estimated to be approximately 100m3 per day. In this phase, the efficiency of anaerobic treatment system was investigated. The parameters measured in this study were BOO, COD, N03, P04, TS, OIL, and grease. After the samples were analyzed, the removal efficiency of the organic elements turned out to be low for the anaerobic system in winter. Phase Two: This phase lasted from September 1, 2004 to December 29, 2004. To increase the efficiency of the anaerobic system, a fixed-bed was installed. As a result of the improvement of the system, the following findings were obtained for the two years of 2003 and 2004: - An increase in the BOd removal efficiency from 30% to 61.4% - An increase in the COD removal efficiency from 45% to 64.6% - An increase in the N03 removal efficiency from 58.5% 82.8% - An increase in the TS removal efficiency from 63.8% to 67.9% - For the P04 removal efficiency, no significant difference was observed. The results for the aerobic system after its improvement are as follows: - An increase in the BOd removal efficiency from 83% to 90.5% - An increase in the COD removal efficiency from 82.2% to 92.2% - An increase in the TS removal efficiency from 72% to 80% - For the P04 and the N03 removal efficiency, no significant difference was observed.

Due to the growing population and oil-dependent industries, the demand for oil products has risen. The increase in oil production, and consequently the higher consumption rate together with the careless use of oil products have aggravated the contamination of water and soil resources, which in turn has led to serious, and sometimes irreparable, harms to the environment. The amount of the leached contaminants, the flow path, the contaminants' traveling time in soil and water resources, and the concentration of pollutants in various depths are the main points the policy-makers need to determine.In this study, the researchers utilized a model called RITZ (Regulatory and Investigative Treatment Zone Model) to model the oil products' leaching into the soil and groundwater resources. This model is used not only to evaluate the leaching process, but it also helps us to locate the contaminated zone and to measure the pollutant's concentration. For the calibration of the model, the output data from the RITZ model were compared with the laboratory data as reported in the previous studies. The obtained high correlations and the other results are shown in different tables and graphs.

At 5:27 a.m. on Dec. 26, 2003, an earthquake measuring 6.6 on the Richter scale struck the city of Bam in Kerman province. As a result of the quake, the city's buildings and installations were badly damaged and over 30,000 people lost their lives. In such a situation, the production, supply, and distribution of foodstuff is very hard and providing healthful food is difficult for long after the disaster.This cross-sectional study was conducted in order to learn about the health conditions of the food supply and distribution centers after 9 months past the quake. To this end, a checklist and certain forms were prepared. The checklist included such parameters as the water supply system, sources of water, types of building, wastewater disposal condition, types of floor, air-conditioning and lighting conditions, screens, valid health cards, trash cans and disposal, the condition of water-closets and baths, refrigerators and freezers, cold rooms, and personnel. Using simple random selection techniques, 67 active shops were studied: 17 grocery stores, 13 fast-food places, 11 butcheries, 10 dairy shops, 7 chicken stores, 2 bakeries, 2 restaurants, 2 ice-cream shops, 2 food distribution centers, and 1 confectionary. The results showed that 58.2% of these centers had piped water 7.5% had water tanks, and 34.4% were without a water system. Moreover, 52.2% of food supply centers were made of bricks, 34.3% were temporary conex containers, and 13.4% were tents. Furthermore, 44.8% of these places discharged their wastewater into ground wells and the remaining 55.2% did not discharge their wastewater hygienically. The conditions of solid waste collection and disposal, water-closets and baths, freezers, and the personnel needed modification and improvement.

In the present world, in which all people force themselves to follow the environmental regulations, environmental assessment is necessary. For all big projects, there are some challenges in the field of wastewater treatment, specially the activated sludge system. These challenges are about the production and the disposal of excess sludge produced in wastewater treatment plants. Minimization of sludge production in wastewater treatment plant with the activated sludge system by the optimization of treatment parameters is the aim of the present study. For this purpose, a pilot laboratory was installed in the civil engineering department of K.N. Toosi University and the wastewater was supplied from Shahrak-e-Qods wastewater treatment plant.The results obtained form sampling and laboratory tests were noticeable: the excess sludge production reduced by raising the oxygen concentration in the mixed liquid. Also, a decrease in the loading of the sludge entering the aeration tank resulted in a decrease in the produced sludge. Finally, a mathematical model for the simulation of activated sludge floes and the description of the effects of the above-mentioned parameters was developed.

Since 1992, the Convention of Climate Change (UNFCCC) and the Kyoto Protocol have been among the important environmental activities of the international community. As the Kyoto Protocol has various effects on the economic, technical, and social activities of the developing countries, especially the oil-dependent nations which are in the early stages of sustainable development, analyzing the effects of this protocol is very important. The economy in Iran is dependent on oil and gas, and the country is located in an arid or semi-arid region, with many endangered natural resources. At the same time, the energy saving activities, substitution of clean energy resources, improving energy efficiency, and the like have had many obvious effects on reducing the emission of various gases and also decreasing the environmental pollution in recent years. The Convention and the Protocol, the economic and environmental models for Iran based on the climatic changes, and also the ecological effects for the country are studied in this paper. In the end, the challenges and the opportunities of this Protocol are discussed.

IFurnace is the main consumer of energy in petrochemical and refinery processes. Its main use is in heat cracking and preheats process fluid. The increasing oil prices in the late 20th century led to the emergence of energy optimization methods. In this paper, the effect of different optimization methods on the important environmental factor in furnaces, i. e., polluting gases caused by the combustion reaction, is studied.The main pollution factor in furnaces which burn sulfur-free gases is the reaction of matters and the production of Nox. After studying the analyses obtained from a sample furnace, certain methods were proposed for the optimization of energy and the reduction of environmental pollutants.The results show that to optimize a furnace without using a NOx-reducing device the two methods of reducing the extra air and pre-heating the air, the extra air is reduced by 33% and 43%, respectively.

Polycyclic aromatic hydrocarbons (PAHs) are among important polluting compounds that contain Benzene rings in their molecular structure. They enter water ecosystems from a variety of sources such as Petrochemical industry, urban sewage, ships, oil spills, and the like. These compounds have been shown to have many harmful effects on human beings, including cancer and other serious diseases. One of the effective methods of decreasing or eliminating PAHs contamination is through the use of degradading bacteria.In this study, phenanthren-degrading bacteria were isolated from southern Caspian Sea waters. The water samples were collected from two important shipping ports in southern Caspian Sea in spring and summer, 2005.

A vast variety of microorganisms secrete surface-active compounds, hence their name, biosurfactants. The secretion of these compounds by microbial cells facilitates the absorption of insoluble substrates. The most valuable application of biosurfactants is in petroleum industry where they are used for improving quality, facilitating extraction, and decreasing viscosity. This study is aimed at the isolation and identification of biosurfactant-producing bacteria and the assessment of their potential application in the removal of oil pollutants. To this end, samples from 86 different sites including petroleum wells and sites polluted by oil compounds were selected. Then 158 strains of bacteria, 10 strains of actinomycetes, 9 strains of molds, and 2 strains of yeast were isolated from those sites. After that, using emulsification tests, we studied emulsification capacity of the isolated strains. As the second step, we demonstrated biosurfactant secretion by the strains through measuring the surface tension. Finally, through measuring the surface tension, 9 bacteria strains were selected from the isolated strains, all of which caused a decrease higher than 20 dyn/cm2 in surface tension. The induction effect of biosurfactant secretion in the isolated strains was also evaluated. Among the important features of the isolated strains, one is their high salt tolerance and their successful secretion of biosurfactants in a vast pH domain. In this way, the researchers could demonstrate the proper capacity of the strains in removing oil pollutants and their application in the microbial enhancement of oil recovery.