JOURNAL OF ENVIRONMENTAL SCIENCE AND TECHNOLOGY
Year:2005 | Volume:- | Issue:25|Papers Count:13

To investigate the possibility of using photovoltaic lighting systems for the roads of district 22, different scenarios were calculated using the renewable energy model with one to three 45-W solar modules installed on a single light- post. The results of the study show that light-posts with three 45-W solar modules can be proposed for parks, green spaces, and small parking places.

Due to the importance of air pollution caused by radioactive elements at the site of Tehran Research Reactor, the plants, air and soil of several stations around the reactor were sampled in the year 1382. Gamma - Ray Spectrometry was used for activity measurements. The results indicate that, during the stability condition of the air, the increase and decrease in the activity level at the stations are very close to each other. The level of Radon concentration in the samples depends on the temperature and humidity of the air. The sampling time of 6-7 hours was the best condition for the determination of air pollution. Due to the absorption of radioactive elements on the surface of the particles, any increase in the particles in the air, caused by the stability condition, can increase the level of radioactivity in the sample.

Mass transfer between gas phase and liquid phase occurs in different ways in a large number of industrial processes and many engineering disciplines such as environment, gas refineries, and chemical and atmospheric sciences. An improved mathematical model for liquid film columns is presented. This paper describes a theoretical analysis of the combined hydrodynamics and mass transfer for the process-taking place in liquid film with the absorption of gas for annular regime through a vertical pipe. In this study, the flow of the liquid film is turbulent and wavy. We used k -ε model for eddy viscosity. For the wavy surface in annular flows, the Suzuki model was used. The theoretical results were compared with the experimental data for the mass transfer gas (CO2) in water (H2O), and the obtained results were satisfactory.

Heavy metals are present in different types of industrial effluents and contribute to environmental pollution. Application of algae for separating the metals from polluted waters and wastewaters is a new and effective method because in this method, there is little slug and the metals and biomass can be recycled. The recycle experiment showed that using HCL (pH=2) and EDTA (4 milli mol), the recovery rates are 75 and 85 percent, respectively. The repeated application of HCL and EDTA in consecutive cycles leads to an increase in the metal remaining in the algae and a decrease in the recovery rate. So, after 5 consecutive cycles, there is a 90% decrease in the recovery rate due to HCL and 65% due to EDTA. In the first cycle, in which the highest amount of heavy metals is recovered, the building cost of the recycling system is about 90 times and the annual investment cost is about 350 times of the value of the recovered heavy metals. As the number of cycles increases, the recovery costs increase, as well. Therefore, due to the low price of heavy metals and biomass and the high price of the recovery system, the recovery of these elements is not economical.

In this research, the effect of atmospheric pollutants on antioxidant enzymes activity and soluble carbohydrates of Lavandula vera and Rosmarinus officinalis is studied. The data from DOE air quality monitoring stations were considered and the stations with the highest and lowest amounts of pollution were selected. Then, the two plants were planted in both stations. After one year, the plant leaves were harvested and studied. The results of the study showed that enzymes activity increased in the more polluted site. And there was a significant difference between the treatment and control cases. The activity rate was higher in Lavandula vera than in Rosmarinus officinalis.Also, the soluble carbohydrates increased and were positively correlated with pollution stress. Variations of soluble carbohydrates in the two plants were significant.

In Tehran, 18,596 tons of construction refuse is daily produced that has an undesirable quality. The solid refuse management requires the knowledge of collecting, recycling, discarding and also finding out the constituent parts of construction refuse. This survey represents the opinions of the executives of the municipalities in Tehran regarding the process of collecting, discarding and recycling the construction waste.The demolition and construction of administrative, commercial, and residential structures are the main source of such waste. The amount of construction refuse in Tehran between 1373 and 1382 is estimated at 97,102,198 tons, of which 6,787,603 tons were discarded in the pits of the capitals suburbs in 1382.In Abali pit, the quantity of construction waste amounted to 4,878,058 tons (the same year) that was transported by 531,900 trucks. The figure comprises 72% of the entire discarded refuse in the pits around Tehran.According to the investigations conducted in 1382, the ratio of recycled waste to the total amount of waste in Abali pit has been 11.62× 10 percent that includes 6.1×10 percent of brick, 2.5× 10 percent of tin sheets and iron cans, 1.6×10 percent of iron and metal ware, 0.98×10 percent of various sorts of metal pipes, 0.4×10 percent of plastics and plastic gunnies, and 0.09×10 percent of Aluminum. Meanwhile, brick with 51% forms the highest amount of all recycled materials.In comparison with the developed countries such as Denmark, where 95% of the construction refuse is recycled, Iran possesses a great potential for investment in this area.Nowadays, in advanced countries, recycled pebbles made from a combination of debris, are used in cement and the production of concrete. Also, brick pieces are used as one of the constituent parts of pebbles and glass fractions are wielded in asphalt or tar-bound roofing.In line with the sustainable civil development, the above-mentioned substances can be used as filling, drainage, and substructure materials in designing parks, flattening declivities, making precincts and, constructing roads. At present, the storage, collection and transportation of such refuse is carried out by non-governmental organizations supervised by Tehran hygiene department affiliated to the Recycling Organization.Developing a systematic method for collecting, transporting, discarding, and recycling of soil and construction refuse in Tehran is an effectual step towards the advancement of the goals of the sustainable civil development.

Externalities and damages from externalities are unavoidable in economic processes. One of the important externalities is environmental pollution. Therefore, in order to control pollution, society must suffer social costs. Social cost in energy sector is created because of greenhouse gases (CO2, SO2 and Nox). In this paper, methods for social cost estimation and experiences of other countries in this field have been studied.Trend of social cost of energy sector in Iran shows 139% of growth rate. So, native coefficients for social cost estimatation are very important. Also, it is necessary to mention that damage cost of energy sector in Iran hace been 52050 billion Rials, which 12.9% of it belongs to power sector.

The measurement of food radiation, as one of the most important parameters in food consumption safety, is performed according to current regulations and standard tests in most countries including Iran. Due to the presence of low-level radiation in food samples for gamma-ray spectroscopy, using lead shields for reducing the background radiation is recommended. In this research, the influence of lead shield on NaI (Tl) detector background is investigated and the amount of detection efficiency and MDA (Minimum Detectable Activity) with and without lead shield is evaluated. The results show that a properly designed lead shield is necessary for low-radiation measurements. The shield discussed in the present study can improve MDA value for more than 100%.

To develop a desirable atmosphere, people do not always wait for a designer. They may not have enough visional knowledge or innovative powers for designing, but they can acquire them. They use their innate sense of aesthetics and their neighbors trial and error to eliminate the unpleasant elements of their surroundings and change them into pleasant ones. Green plants are among the aesthetics elements of the environment although it is difficult or even impossible to make green spaces in residential areas, specially in apartments; but the innate sense mentioned above looks for suitable ways to solve the problem: putting some flower boxes at the windows or growing a lot of bobbins from the roofs towards the yard, and the like. In this article, it is tried to classify the creativity of people in this regard by reviewing the pictures of more than 200 buildings in the city of Tehran. The results can change into patterns for compensating the lack of green spaces and making the views of buildings pleasant.