JOURNAL OF ENVIRONMENTAL SCIENCE AND TECHNOLOGY
Year:2007 | Volume:9 | Issue:3 (34)|Papers Count:16

Water is the most important and the main solvent in the nature. Almost all compounds, even to a little extent, can be solved in water and for this reason, water contains many impurities. Nitrate is known as the last stage of nitrogen compound oxidation which causes meta-hemoglobin in infants and forms carcinogenic nitrosamine compounds.Nowadays, various physico-chemical and biological processes are used to remove nitrate from drinking water. One of the most practical physico-chemical nitrate removal methods is the ion exchange and membrane processes including nano-filtration and reverse osmosis.The main objective of the present study - considering the above-mentioned points - is the evaluation of nanofiltration and reverse osmosis efficiency for the removal of nitrate and other ions. This study was conducted over a sixteen-month period (August 2005 to December 2006) using nano-filtration and reverse osmosis pilot.In this investigation, a domestic reverse osmosis treatment pilot and an industrial nano-filtration pilot were used. By increasing the nitrate concentration in water and by adding chloride and sulfate ions with different concentrations, it was tried to investigate their effects on the nitrate removal process.According to the obtained results, by increasing the nitrate concentration, the efficiency of both nano-filtration and reverse osmosis systems for the removal of nitrate decreased. In this study, the highest efficiency in both systems for removal of nitrate was observed in the concentration of 25 mg/l. In both systems, for the effects of sulfate and chloride on nitrate, a synthetic solution of sulfate and chloride was prepared and along with nitrate was injected into the system. During the investigation, the effects of each one of the ions on the mentioned systems were studied. Also, by increasing the sulfate and chloride concentration, the efficiency of the systems in removing the nitrate decreases.In a homogenous concentration of the mixture of nitrate and sulfate in drinking water (100 mg/l), sulfate is removed by the systems to a larger extent, but in a homogenous concentration of the mixture of nitrate and chloride in drinking water (100 mg/l), mostly nitrate is removed. At equal concentrations, nitrate removal efficiency in nitrate compound with sulfate is higher that that in nitrate compounds with chloride. The highest efficiency obtained from nitrate removal experiments are 95.6% and 93.4% in nano-filtration and reverse osmosis systems, respectively.

Chah-Nimeh reservoirs of Zabol are three natural and big cavities in the south of Sistan Plain in south-eastern Iran and cover an area of 50 million square meters. The water stored in these cavities is used to irrigate the Sistan Plain and to provide the potable water of Zabol and Zahedan. Despite the apparent importance of Chah-Nimeh lakes, no research has been done on the quality of their water except for the study of the sediments and the limnologic study of the reservoirs.To determine the quality of the water, some of the physical and chemical characteristics (14 parameters) of Chah-Nimeh reservoirs were investigated in 9 selected stations from the fall of 2004 to the mid-summer of 2005 and the samples were collected on a seasonal basis. The results show that the means of COD, BOD5, nitrate and nitrite in all stations and seasons are very small and can cause no problems. The amount of phosphate is lower than the standard level except in the third station. The quantity of the dissolved oxygen is suitable in all seasons. But on the average, the dissolved and suspended solids, hardness, turbidity, and electrical conductivity are high in all of the three Chah-Nimeh reservoirs, which can be attributed to the atmospheric conditions and high temperature of the area, sand storms, and the type of bed soil of the lakes.

Because of its exceptional situation, the Asalooyeh region in the Persin Gulf has become the site of many plants and gas refineries, and its waters are directly and indirectly being polluted by mineral and organic materials.Due to the situation of this area and the limited number of researches which have been conducted, the present study was done on the sediments and the water of the zone in order to measure the amount of heavy metals as a benchmark for evaluating and measuring these materials in future when more gas refineries and petrochemical plants become operational.Measurement was based on commonly used standards (1 and 2), using an atomic absorption spectrometer. Compared with those obtained in some other areas in the Persian Gulf, the results indicate a low concentration of heavy metals in the sediments and water samples, which cannot be attributed to the gas refineries. The minimum and maximum rates of the measured metals in terms of ppm are as follows:Ni: in the water (0.17- 0.23), in the sediments (19.9-27.2),Pb: in the water (0.13-0.14), in the sediments (20.2-29.5),Hg: in the water (0.0001), in the sediments (0.02-0.025).

This study aimed at finding a way for the remediation of toxic and radioactive pollutants. After studying different areas, the researchers succeeded in isolating an Iranian native bacterial strain that could produce a kind of exopolymer in large quantities. This exopolymer plays a key role in metal adsorption; that is, the increase in metal absorption is directly related to the secreted exopolymer. The results of the experiments show that uranium and cadmium uptake by bacterial biomas was 550-800 and 800 mg metal per one gram of the dry weight. Compared with those of other studies, these amounts are remarkable and the microorganism is reported as the second in the world after Citrobacter sp. The results of the investigation on the removal rate of toxic metals and radionuclide from the polluted waste in the bio-reactor revealed that this system is capable of bioremediation of U, Cd, Pb, Ag and Ni as much as >99, 99, 90, 72, and 57%, respectively. Calcium chloride plays a very effective role in the formation of biopolymer flocks and in increasing their precipitation rate in the bioreactor. Consequently, this biopolymer can be used both as a bio-resin and as a bio-precipitator for bioremediation of nuclear wastes.

Due to the close relationship between the energy and environmental problems, recovering technology and optimizing energy consumption have a major role in environment protection by minimization the atmospheric pollutants such as. This minimization may decrease the greenhouse effect, and the ozone layer destruction. On the other hand, optimization of Energy consumption and its recovering may minimize the water and hot oil consumption at the heat exchangers (reboilers and condensers) in petroleum distillation columns, specially. The present research has been performed about the kerosene pre-fractionation unit of one of the country's oil refineries. This system includes two distillation columns with a simple arrangement. Considering that the distillation section consumes a great deal of energy in the chemical and petroleum industries, hence studying the ways in which we may decrease this consumption is of great importance. One of these retrofit solutions is the heat integration, which is going to be presented in this research with a different idea from the other previous methods. This method makes it possible to add a shell and tube heat exchanger for doing a part of condensation and evaporation operation which can decrease the heat duties of reboilers and one of the condensers. To this end, the distillation columns were studied in the process and then the proposed model of columns arrangement were simulated by heat integration with all input and output streams using the  spen Plus software, version 10.2 and the Rad Frac model in this software. The result has showed itself as a save of 10.84 % in water consumption, a 14.23% saves in energy consumption, and a 14.23% save in hot oil consumption.

One of the key points in providing healthy conditions for people is to prevent water-borne diseases. Therefore, wastewater treatment plants play an important role in promoting public health and environmental protection. Following the establishment of rural water and wastewater companies in Iran, sanitary disposal of wastewater may be considered through a comprehensive plan.Having the mentioned objectives in mind, the researchers planned the present study. With the major goal of presenting an optimal strategy and methods for treatment and disposal in rural areas throughout the country and after collecting basic information on the situation of villages in Iran (population, climate and water supply), the research was conducted.First, the necessary data about the sewage collection and disposal system were gathered through questionnaires. Second, based on the fundamental criteria of sewage collection needs, villages were classified and ranked. Villages were classified into 6 groups based on the conditions of climate, ground water table and soil structure. Of course, our conclusions must be considered as guidelines. For a decisive conclusion, it would be necessary to consider local specifications and very special conditions as other sub-criteria in the study.

Haraz River (181 Kmlong) flowing a long distance, passes through the city of Amol and flows towards the sea in an area named Sorkhrood. The watershed basin of this river is 8513.6 Km, which is located in such cities as Amol, Babol, Mahmood-Abad, Fereydoon-Kenar, and Noor and considered as part of the agricultural lands of Mazandaran Province.To study the pollutants of Haraz River, three hydrometric stations called Panjab, Karesang and Sorkhrood were chosen. After determining the area under study, some samples were obtained in different seasons in 1382. Then, the graph of the results was drawn by Excel software and compared with potable water standards. By studying the indicators of the river's water quality in the years 1380-1382 and 1359-1375 and comparing them with acceptable standards, maximum permitted limits for drinking water, and the pollution concentration of drinking water, it became clear that that the quantity of DO, BOD, COD, NH3, EC, Turbidity, Color and number of Coliforms were more than the standard limits, which might be caused by environmental changes and by the wastewater flowing into the river. An increase in rainfall in autumn leads to an increase in the quantity of BOO, EC, ms, TSS, NO3, and P04. It is to be mentioned that the type of vegetation can also play a role. In the upstream where the coniferous trees are not very thick, with an increase in the rainfall, the quantity of TDS in the downstream increases. Comparing the pollution indicators of the years 80-82 with those of 59-75, it was seen that the amount of DO during the years 59-75 was in an acceptable range, but during the years 80-82 and due to the wastewater flow into the river, the amount of DO has decreased about 0.6 times. COD and BOD were found to be beyond the permitted range in 1359-1375. COD was 0.8 times lower during the years 80-82 than the years 59-75 and BOO was 1.06 times more during the years 80-82 than the years 59-75. Ammonia in the years 59-75 has also been more than the permitted limits, which shows contamination by domestic wastewater. The amount of EC was 1.3 times lower during the years 59-75 than the years 80-82, which can be due to the industrial wastewater flow into the river. The amounts of Turbidity, Barium and Color during the years 80-82 have been higher than the permitted limits for potable water. Meanwhile, the amount of TDS is lower than the desired limit despite the fact that it has increased by 1.05 times compared with the years 59-75. Moreover, with regard to the number of Coliforms in the years 80-82, the river's water was classified as suspected. At the end, it should be mentioned that we need to prevent the flow of agricultural and urban wastewater into the river in order to have an optimal management for Haraz River.

Jahan-nama protected area (category V in the United Nations list of national parks and protected areas) is located in Alborz mountains in the north of Iran. Its total area is 30600 ha and it has a beautiful landscape, pleasant climate especially in summer, rich flora and fauna, and many historical monuments. In this area, there are also four villages with their unique characteristics.The aim of this survey was to study, develop, and enhance the ecotourism of this area. The area was visited several times during summer and early autumn, 2003. Field studies show that there are three types of visitors, namely hikers-climbers, native people, and other visitors, each with their special environmental impacts. The area's infrastructures include local transportation, rural accommodation, scattered trails, unsuitable roads and poor service centers. Since tourism has been one of the primary goals of category V regions, and most northern areas in Iran have the potential ecological capacity for extensive tourism (hiking, climbing, wildlife watching, etc.), the proposed ecotourism management in Jahan-nama includes the following:1) Ecotourism management strategy in Jaghan-nama protected area must--conserve biodiversity, local ways of life, and traditions;--establish self-financing mechanisms;--set up local and public participation in decision-making, planning, and management processes of ecotourism;--interpret environmental issues for ecotourists in order to educate them;--create social sensitivity to the environmentally abrasive decisions against the area; and finally--cooperate with national and international ecotourism organizations and programs.2) Ecotourism management plan includes:--Establishment of four proposed management zones (zones I to IV);--Creation of a monitoring system, i.e., environmental impacts assessment (EIA), an environmental auditing system, and an environmental management system (EMS) in a long-term process;--Analysis of the visits to the area at several points by using questionnaires;--Creation or adaptation of physical facilities including alterations in the western road;--Creation of few nature trails in the centre, south and north-east of the area;--Improvement of rural accommodations;--Improving and designing sanitation systems such as waste treatment and recycling units; s--Provision of two centers in the area for the visitors;--Designing interpretation and educational programs for ecotourists, local people, government authorities, investors and entrepreneurs, NGOs, and protected area managers, support staff, park rangers, etc.--Marketing of ecotourism based on the characteristics of ecotourists;--Creating a self-financing mechanism including types of user fees in the area such as fees to operate restaurants, ecolodge facilities and souvenir shops; entrance fees;fees to use campsites and visitor centers; fees on recreational equipment; sales of educational materials; permits for tour operators and guides; green taxes on litter, etc. --Designing environmental codes of conduct for ecotourism and generating guidelines for ecotourism industry, local people and ecotourists.Integration of environmental, economic and sociocultural elements and monitoring Jahan-nama ecotourism management plan will conserve and improve environmental, economic and sociocultural conditions of the area. So, in the future, Jahannama protected area will be an important ecotourism region in Iran.

Taleghani forest park with a surface area of about 29 hectares is situated in the northern part of Abbasabad district. This park is limited from the north to Haghani Blvd, from the west to Modares highway, from the east to the Eastern Street of the park, and from the south to Hemat highway. It is one of the recreational sites in the city of Tehran.The aim of this study is to estimate the economic-recreational value of Taleghani forest park by Clawson method and the results can be used as an effective tool in the planning and management of development projects.This method is based on the estimation of the relationship between the number of people who visit the park and the average distance of their living places from the park as well as the average access cost.To this end, six circles with equal distances of 3300 meters were drawn, with the park as their center.Then, by using maps and existing statistics, the surface area of each region and its population were calculated. After that, the socio- economic data extracted from the visitors' completed questionnaires were analyzed and the curve showing the relationship between the access cost and the number of visitors to this forest park was drawn. Meanwhile, the calculation of different entrance fees was done and by adding them to the total access costs, the new ratio of the visitors was obtained and the curve of demand for Taleghani forest park was drawn. Ultimately, by estimating the surface area under the demand curve, the daily recreational value of Taleghani forest park was calculated to be 42, 400, 500 tomans. The analysis of the extracted social data shows that most visitors of Taleghani forest park are in age range of 20-25 years and that most of the subjects had a high-school diploma or university degree.

This research studies the toxicity effect of vanadium and nickel compounds on Artemia urmiana and Artemia franciscana under laboratory conditions in short-term (acute) methods. While performing the experiment, the physical and chemical characteristics of water such as temperature, pH, soluble oxygen, hardship and electric direction were controlled. The experiments were done on the control group which received no metal, and 17 treatment groups which were exposed to different concentrations of nickel and vanadium.The amount of LC50 vanadium and nickel was 0.01146 and 0.007201 ml/lit for Artemia urmiana, and 0.01158 and 0.0107 ml/lit for Artemia franciscana. The results showed that nickel and vanadium had toxic efforts on the two species of A. franciscana and, A. urmiana. Although both species showed a high resistance against nickel and vanadium, the toxicity effect of vanadium on A. urmiana was more than that of nickel. However, the toxicity effects of nickel and vanadium on A. franciscana were the same and no significant difference was observed.

To identify and estimate the population of fishes in Namroud river (between Namroud Bridge and Tehran Gezel Breeding Center), a period of sampling was done in June, 2004, using an electro shocker. Sampling was done in one phase and in a zigzag over a length of 600 meters, and 43 fishes were hunted altogether. The results showed that the fishes were of 6 types:Alburnoides bipunctatus (Bloch, 1782), Capoeta aculeata (Valencienns, 1844), Capoeta damascina (Valencienns, 1842), Leuciscus cephalus (Linnaeus, 1758), Nemacheilus bergianus ( Derzhavin, 1934) and Oncorhynchus mykiss (Walbaum, 1792).The population estimation of each species was done based on their ratios in the sample. Considering the obtained species, type of river bed, and temperature and speed of water, it seems that the region under study should be considered as a Sub Mountain Zone according to Holcik-Hensel classification. Such regions have Barbel, Grayling, and Trout. These kinds of fishes are not only native to the region, but they have also come via the exit canal of Tehran Gezel Breeding Center and have survived due to suitable environmental conditions.

In order to prevent 'Environmental degradation' and promote 'Sustainable development', various tools like 'Environmental Law', 'Environmental Audit. 'Environmental Science and Engineering'; 'Environmental Impact Assessment' and 'Environmental Awareness and Education' are being used widely now-a-days. 'Environmental Education' is a powerful tool which can enhance peoples awareness. This tool can be operated through the formal and non formal educational systems. Hungerford's infusion and diffusion models of curricular pattern define environmental education in two different ways. This paper discusses the need for a change in the curriculum and objectives of Environmental Education and current global and Iranian scenario of Environmental Education. It also compares the infusion and diffusion models and suggests that the content areas for inclusion in the formal programs of technician training curricula and activities be integrated in the functioning of the community polytechnics. The study concludes that the infusion model that integrates environmental components into technician curricula is more relevant because it produces environmentally literate Engineers and Technicians for promoting Sustainable Development.