JOURNAL OF ENVIRONMENTAL SCIENCE AND TECHNOLOGY
Year:2008 | Volume:10 | Issue:2 (37)|Papers Count:16

To examine the efficiency of SBRs in the treatment of industrial wastewater containing PSA and their operation in eliminating different amounts of PSA, two cylinder reactors equipped with an intelligent system were designed and built.Also, an artificial wastewater containing protieds and lipids with COD equivalent to 600 to 100 mg/lit was prepared. Following the mixture of the specified volume of return sludge of the wastewater treatment unit of Shahrak-e Gharb, the compatibility and conformity of microorganisms with the existing conditions were examined in the laboratory for 56 days with a 10-day bacteria residence time.The results of the study show that the elimination of COD (93-97%) in compatibility and conformity conditions of microorganism is high and considerable. SBR is completely effective in the elimination of both different concentrations of PSA (up to the 60 mg/ l) and COD. However, the percentage of the elimination of COD waste is not very much.By increasing the concentration of PSA, the MLSS in the reactor decreases. But it takes an increasing trend as a result of the compatibility of microorganisms which is due to the toxicity of this composition and to the death of the bacteria. The death of the bacteria could be the result of the destruction of the membranes, the genetic influence, and bursting due to the absorption of too much water.An increase in the concentration of PSA resulted in the increase of SVI, but it took a decreasing trend after compatibility and conformity. The decreasing process could be due to the absorption of water by microorganism for diluting the poisonous substance in the microorganism plasma.By increasing the concentration of PSA, its elimination decreases in each stage. But after compatibility, the percentage of microorganism elimination increases.

Waste minimization management systems are one of the effective methods of reducing wastes production in all industries and service units. In such systems, the main goal is to seek all the possible ways of minimizing waste production.In this study, one of the country’s detergent-production factories, Tazh detergent factory, was chosen for case study.After gathering the general information about waste minimization management systems and studying the different activities of a detergent industry, the main parts of the factory were identified. The results of the study show that the major units producing wastes in this plant are powder and sulfunation units. Application of waste minimization management systems in these units reduced waste production by about 18% and about 84 million rials was saved, a considerable figure considering the total costs of the units.

Electric power plants are one of the sources of energy. As power plants meet the main and basic needs of man, they are considered to be very important. Electric power plants produce pollutants that endanger human life. Therefore, it is vital to pay special attention to control and prevent the emission of air pollutants such as NOx and SO2. To this end, the present study aimed at investigating the above-mentioned pollutants and their distribution using Screen-3 software. A distribution map was processed in Arc view software. Finally, iso-maps of pollutants concentration were drawn. Two of the four power plants studied, namely Rey and Shahid Rajaee, emit more pollutants than the other two. Loushan and Ramin Ahwaz power plants emit pollutants within the standards limits. In the end, various methods of pollution control were studied and the most best adoptable ones were selected for the studied power plants.

In the course of the industrialization of Tehran, there has been no assessment as to the effect of development (regarding the location of the industries) on the environment to achieve sustainable development. Therefore, these industries are located in residential areas and cause troubles such as traffic and environmental pollution. Besides, the shortage of contamination controlling systems have made residential areas unsuitable places to live in. Moreover, not having enough spaces, theses industries face lots of problems for their future growth. To solve the problem, the government ratified the transfer of polluting industries from Tehran to suitable zones confirmed by the Environment Protection Organization. Thirty-three polluting industries-such as electroplating workshops – were identified and transferred to Kharazmy Industrial Complex. Now, the main question is whether the transfer of these industries has had any effect on the quality of life in residential areas and if the answer is positive, to what extent people’s lives have improved.In this study, it has been tried to investigate the industrial complexes and estimate the cost of damages to the environment and to the people. So, municipal district number 12 has been chosen. The tendency of the affected society to move to the new zones is studied and the amount of damages to the environment is estimated through theoretical and practical ways, interview with environmentalists, searching the Internet, and observation.

In the sector of electricity production, environmental issues and the limitation of investment sources are the main factors that influence the process. The reduction of costs and the destructive impacts on the environment have always been mentioned by specialists. Consequently, the seriousness of the environment protection and the production of electric energy have led the authorities to focus on solar power plants. It is obvious that the issue of required resources for investment surpasses the environmental factors in our country. Here, the main question is whether in the current situation of our country, the replacement of fossil power plants with solar power plants is possible or not and whether we can be hopeful about such possibility in the future.Considering the high costs of electricity production by solar power plants and the situation of electricity production costs with regard to the social costs, this study aims at doing an economic evaluation on the above-mentioned issue in Iran.In this study, the marginal cost of 1kwh electricity production in each power plant was estimated. Then, an evaluation was done considering pollutants and greenhouse gases emitted from fossil power plants. The imposed social costs were also taken into consideration. In conclusion, it is shown that the use of solar power plants electricity is not economical yet; however, photovoltaic systems are economical in the same situations. Regarding the increasing demand for electricity, the scarcity of resources, and the large amount of pollution, fossil power plants will not be economical in near future.

In this study, a method has been developed to estimate the damages to logging and timber skidding on regeneration and stands in forestland. The forests of Wood and Paper Industries of Mazandaran were selected for case study. Three forest regions including parcels number 17 and 28 of Waston and parcel 7 of Alandan districts were selected for the study because they enjoyed medium, generalizable characteristics among the company’s forests. For the economic evaluation of the damages on regeneration and stand, each of the estimated factors was changed into a coefficient before being used in the computations. The number of saplings per hectare and the cost of each destroyed sapling were estimated. To evaluate the cost of damages, qualitative data were changed into quantitative ones using expert knowledge based on analytical processes and proposed mathematical relationships.The results revealed that in felling and bucking operations, 3.2% of the regeneration was damaged, of which 5% could be prevented. Also, after winching and wood skidding, 4.8% of the regeneration was damaged, 8% of which could be prevented. During logging operations, a total of 51,147 rials of preventable damages per hectare is inflicted to the regeneration. On the stand, felling and bucking operations damaged 13.6% of the remaining trees. The damage is about 1, 512, 335 rials per hectare. After skidding or at the end of the logging operations, the total amount of the damages to the stand was 15.5% and its preventable economic value was 3, 544, 356 rials per hectare per year in the logging area. In fact, the economic damages caused by felling, bucking, and skidding amount to 3, 595, 503 rials per hectare in the logging area.

Shahryar is located in the west of the Tehran Province with an area of 1,329 km2 which covers 7% of the area of the province and 9% of its population. Due to the increasing need for establishing industrial units, Shahryar has fallen into an unplanned development process which can cause irreversible environmental losses in the future development trend.The results of the present study show that the number of factories equipped with suitable treatment systems is very limited and it can be said that the industries mainly discharge their sewage without any treatment or with an incomplete treatment process. Improper disposal of solid wastes in industrial units is another problem. Current waste disposal sites are also major pollution sources due to improper disposal. The most commonly used fuels in industrial units are gas oil and mazut with considerable air pollution potentials. In this research, the existing pollution sources are considered and at the end, certain suggestions are made for the reduction of their adverse effects.

Due to the existence of huge oil and gas resources and special environmental conditions, the region of Persian Gulf and the Sea of Oman is of great importance. The strategic importance of the region as well as military and political tensions and economic issues have all undermined such important issues as the pollution of marine environment and have turned the Persian Gulf and the Sea of Oman into one of the most polluted marine environments of the world. Many international and regional conventions have been established to prevent and control marine environment pollution. International Maritime Organization (IMO) has the responsibility of monitoring and implementing relevant Conventions as well as setting up new rules and regulations for marine pollution at the international level. Although many conventions have been established with regard to marine pollution, very few of them address marine oil pollution: MARPOL Convention, Convention on Compensation Against Oil Pollution, Convention on Preparedness, Response and Combat of Marine Oil Pollution, etc. In order to protect the marine environment of the Persian Gulf and the Sea of Oman against oil pollution, the Kuwait Convention and its Protocols were developed by the countries of the region in cooperation with the United Nations Environment Program (UNEP). In accordance with Article 16 of the "Convention", Regional Organization for the Protection of the Marine Environment (ROPME) was established in 1978 (Kuwait) and based on Article 3 of the "Protocol on Regional Cooperation in Combat of Marine Emergencies", Marine Emergency Mutual Aid Center (MEMAC) was established in 1983 (Bahrain).The results of the survey of international conventions and organizations related to oil pollution reveal that many of the countries are reluctant to join these conventions due to the fact that acquiring the appropriate technology and infrastructure which is a pre-requisite to membership is very costly. Due to the same reason, ROPME member states have different status as far as the membership to relevant international conventions is concerned. Although the Persian Gulf and the Sea of Oman have been declared as "Special Sea Area", none of the existing legal instruments such as the Kuwait Convention and its Protocols contains specific provisions addressing environmental protection of the Special Sea Area.In this study, it has been tried to provide a comparison between the laws and regulation at the national, regional, and international levels to identify the strengths and weaknesses of the existing relevant laws and regulations and to provide comments and suggestions in order to improve the existing legal instruments as well as the institutional arrangements of the ROPME and MEMAC.

After a decade from the preparation and implementation of urban plans, despite various criticisms, no attention has been paid to the implementation issue as a barrier to the urban plans. Approved by the authorities, urban plans aim at developing the cities and creating satisfactory conditions for the citizens. A casual interview method was chosen for data collection in this study. Interviews with city authorities and those familiar with the failures of urban plans as well as empirical observations were the means of data collection. The present study consisted of the following two processes:1. General integrated survey2. Systemic approach surveyIn spite of comprehensive studies and spending a lot of time for the preparation and approval of the plans, certain problems still exist regarding the following issues:--implementation of the plans and the related methods;--systemic relationship between the elements and the structure of the implementation foundation;--financial and human resources;--role of the information flow in the implementation of the plans (lack of feedback);--decision making not under the control of the city managers (lack of dynamism in the plans).Thus, there is a lot of interference in the administration of the city. In fact, there is no executive system. The necessity for planning such a system is quite obvious.

Winter and summer distributions of striped hyaena (hyaena hyaena hyaena) were studied in Khojir National Park, located in the southwest of Tehran, based on 26 field trips from July 2005 to June 2006. The park is 11,570 ha in size. It was divided into 3 sections for observations using such signs as scats, tracks, carcasses, and dens. Altogether, 13 hyaenas were observed and 47 signs noted. Although winter and summer distributions were similar, more signs were noted during summer. Hyaenas were more concentrated in the western parts of the park. Human-related factors that influenced the distribution of hyaenas were also accounted for.

The present study aimed at investigating the effects of 17b-estradiol valerat on gonadal sex differentiation of the rainbow trout in the absorption of yolk-sac stage and the relationship between the immersion period and sex reversal percentage.To this end, 6 days after the hatching of larvae, 750 sac fry larvae were divided equally into 5 treatments. The investigation was performed in one stage and during different times in a bath containing 400 mg/lit of 17b-estradiol valerat using the immersion method. The treatments were exposed to this hormone for different lengths of time: treatment 1 for 1 hour, treatment 2 for 2 hours, treatment 3 for 4 hours and treatment 4 for 8 hours. Treatment 5 was used as the control group. After using the hormone, the larvae were fed and protected to reach a suitable size and the growth of sex gonads for 4 months. After this stage, the fish in different treatments were examined for their sexes in a direct method. The results indicated that 40.40 percent of the fish in treatment 1, 41.5 percent in treatment 2, 54.3 percent in treatment 3, and 59.5 percent in treatment 4 were females. Comparing the results with the sex ratio in the control group -- that included 35 percent female fish and 65 percent male fish -- showed that immersing sac fry larvae in the bath containing 17b-estradiol valerat hormone could lead to sex reversal in this group of fish. But the hormone-treated groups didn't show a significant difference in mean weight and length as compared with the control group of the fish (p>0.05).

Medical wastes produced in hospitals, laboratories, clinics, pharmacies and medical research centers constitute a percentage of daily wastes of the cities (about 2% in Tehran). Such wastes are of a dangerous nature and their disposal needs special attention. Burning is the most universally adopted method used to dispose of these wastes, which takes place at central incinerators. Due to the pollution caused by medical wastes and their burning, the selection of the sites for central waste incinerators is of great importance.The present study concentrates on the site selection for the central waste incinerators in Tehran. From-to chart techniques were used and three feasible locations considering different factors such as traffic networks, environmental limitations, and distances and types of land usage were selected.