JOURNAL OF ENVIRONMENTAL SCIENCE AND TECHNOLOGY
Year:2007 | Volume:9 | Issue:2 (33)|Papers Count:13

Biosorption of stable strontium ( ) and strontium-90 ( , radioactive) by Cysroseira indica brown alga was studied in this research. The optimum absorption pH is 9±0.3 and the highest absorption capacity was seen after 6 hours of contact. Based on Langmuir isotherm, the maximum bisorption capacity was 26.67 mg/g.dry-wt and 10526 Bq/g-dry.wt. Meanwhile, Langmuir coefficients were 0.017 and 0.00006 for and, respectively. Increasing concentration and activity and using more biomass caused an increase in and removal. The dynamic capacity was 14.17 mg/g-dry.wt (:160.97mL/g) in the test column. There is no change in the biomass absorption capacity after 5 times of absorption and desorption experiments using CaCl2, NaCl, CH3COOH and EDTA.

Arsenic is one of the most important toxicants in surface and ground water. Several researchers have studied the use of phytoremediation process for the removal of different pollutants in soil and water. The aim of this study was to investigate the arsenic removal from surface water of Chelpo area in north-east of Iran using the macro-algae, Chara.Four reactors were used in this study with the initial arsenic concentrations of 50, 100, 200, and 300 mgr/L. Besides the assessment of arsenic concentration in water and algae, the pH of the media, and the initial and final weights of Chara were measured.The results showed that Chara could significantly remove arsenic from the polluted water. The maximum arsenic removal was observed in the reactor with initial concentration of 50 mgr/L. The highest arsenic concentration in macro-algae at the end (day 19) reached 62.7 mg/kg dry Chara in the reactor with initial arsenic concentration of 300 mgr/L.

This paper discusses the environmental effects of aquaculture in Iran. When using water as a means of production, two fragile ecosystems require attention: mangroves and coral reefs. About 70% of the annual precipitation in Iran is not being controlled and the inefficient use of the remaining water can lead to high environmental costs.In this study, development capacities as well as the physical and chemical quality of water are considered, with an emphasis on rainbow trout culture. The importance of aquaculture in creating food security for population growth, occupation, and GNP increase is explained and the methods of sustainable development in aquaculture, such as the use of biotechnology and integrated agriculture-aquaculture systems are presented. Feeding management is introduced as a factor in decreasing environmental adverse effects and pollution of raceways effluent is investigated. Effluent treatment with sedimentation ponds, aeration with compressors, and utilization of final ponds are also explained as a means of decreasing environmental adverse effects.

In this study, the toxic effect of acute doses of zinc concentration on Cyprinus carpio was investigated in laboratory conditions.First, the extent of zinc LC50 was measured in 120- to 130- gram fishes. The figures for 24, 48, 72, and 96 hours were 78, 64, 56 and 50 mg/Lit, respectively. Then, the microscopic images of gill tissues of Cyprinus carpio which were exposed to different concentrations of zinc sulfate were studied from a histopathologic view.The obtained results show that exposure to zinc leads to hypertrophy and hyperplasia of gill epithelium, adhesion of secondary lamellae to each other, and considerable increase in mucus.

The control of solid wastes, specially hazardous and toxic ones including hospital wastes, is very important. Due to the prevalence of infectious diseases in the hospitals of Shahr-e-Kord, the diversity of wastes and their inappropriate disposal methods, the presence of various bacteria and viruses, the high level of pollution, the unpleasant smell, and the lack of accurate physical and chemical analysis, the present research is of importance. This study is an applied research which has been conducted for the first time over 13 months in order to compare the technical, hygienic and economic aspects of three hospital wastes disposal methods, namely, sterilization, incineration, and sanitary landfill. The results facilitate the selection of the best method considering the infrastructure and available potentials in Shahr-e Kord. The total waste produced by the four hospitals in the city is 1,500 kilograms per day, of which 45% is infectious litter. The collection of this litter is entrusted to the private sector. Through conducting physical and chemical analysis in the middle ten days of each season, the percentage of different elements in the wastes, the percentage of infectious and non-infectious wastes, the density of the wastes, and the degree of pollution in the hospital wastes were determined. In the chemical analysis, using gas-detection pipes and a special pump, the gases emitted from the incinerator stack were measured and compared with the international standards. The results indicated high levels of emission from the incinerators. The pertinent costs of each method were calculated separately. In the end and after the analysis of the results, the disinfection and sterilization methods were recommended as the best options for the disposal of hospital wastes in Shahr-e-Kord.

Due to having features such as toxicity, corrosiveness, ignitability, reactivity or other similar characteristics, hazardous wastes refer to the wastes that jeopardize man’s health and environment. Hazardous wastes are produced by different industrial, commercial, agricultural or even domestic activities, their risk varies according to the type of materials and environmental conditions, and they can bring about different effects including acute, chronic, short-term and long-term ones. Because of economic and health considerations, a study was required to identify the industrial hazardous wastes in Fars Province, since it plays an important role in the development of the country’s industry. In this study, 101 industrial units were selected and the necessary data were gathered using a questionnaire, interviewing those in charge of the units, and referring to the available documents. The information includes the type and amount of waste, method of temporary storage, frequency of waste discharge, method of final disposal, and the condition of recovery and reuse of waste. Meanwhile, for storing and analyzing the data, an «industrial waste database» was made. The obtained results indicate that 3,011,277.1 tons of wastes are produced each year, excluding the uncontrolled industrial waste water, of which 2,505.52 tons are categorized as hazardous wastes (based on the list of the Basel Convention). Of these wastes, 13.42% are toxic. Besides, 72.12% of the wastes are liquid and 12.63% are solid. It is to be mentioned that there is no temporary storage for 22.92% of these wastes. Moreover, 27.66% of them are disposed of in the environment without any kind of control. Furthermore, all the aspects of the management of hazardous wastes are analyzed and their results presented.

Petrochemical complexes are among the most important industries for the industrial development in our country. Such industries produce wastes which need to be managed. In the past two decades, waste minimization has been considered as a new policy.In countries where there is not enough environmental supervision over the industries, treatment and disposal are more emphasized. Such an approach leads to an increase in costs and in many cases may cause the resources to be wasted. Since waste minimization strategy can reduce the problems, the modern management of decreasing wastes is considered as a national strategy. In this research, the possibility of industrial wastes minimization is studied in the Olefin Plant which is an important unit for producing raw materials for the other polymeric plants in Bandar-e-Imam Petrochemical Complex. To achieve the goals of the study, such issues as the production process, qualitative and quantitative properties, and also reasons for the waste material production were investigated.Both the quality and the quantity of these materials were determined after the identification of waste materials. The results show that 11,972,000 kg of industrial wastes is produced in the Olefin Plant annually. These materials were then categorized according to the method proposed by the United Nations Environmental Program (UNEP). It was determined that 89.67% of the waste materials of the Olefin Plant were hazardous and 10.29% non-hazardous.The hazardous wastes consisted of catalysts, coke, asbestos, used oils and gallons, and polymeric sludge. Then the existing options for waste minimization were surveyed and it was determined that 91% of hazardous wastes could be recycled and 8.94% could be reduced.

The increasing development of stone cutting industries (SCIs) and the extensive use of the different types of stone for construction have led to the increased amount of generated solid wastes in our country, which requires proper environmental management. Considering the importance of the issue, the management of SCIs solid wastes was investigated in Qom province as a case study. Some 55 SCIs were selected and studied. Meanwhile, the disposal sites of the SCLs solid wastes were surveyed as to their environmental adverse effects.The results show that there are 186 active SCIs active in Qom Province, all of which are located within at most 15 kilometers from the city of Qom in 4 areas: Kooh-e Sefid road, old Qom-Tehran road, Kashan road, and Isfahan road. The generated solid wastes are disposed of in 4 sites along these roads. Regarding the number of stone cutting machines (SCMs), these industries are of two types: 151 units have one SCM and 35 units have two. As to the frequency of such factories, most of them (77 units) are along Kashan road. On the average, 50% of the stone used in these factories changes into waste material. The highest amount of waste is related to quarts stones and the lowest pertains to granite stones. The SCIs having one SCM produce an average of 400 tons of wastes per year. The figure is about 600 tons per year for two-SCM units. The total annual amount of solid wastes generated by SCIs is estimated to be 81,400 tons, of which 15,000 tons (18%) are recycled. For complete recycling, the capacity of these factories should increase at least as much as 500 percent. There was no proper management at the disposal sites; therefore, it is necessary to take correct actions for the collection, recycling, and disposal of these waste materials by responsible organizations including the municipality.

Stabilization/solidification (S/S) process is routinely used for the final treatment of the hazardous wastes prior to land disposal. This process is used for treatment of hazardous waste especially heavy metals sludge. In this study cement and silica fume were used to stabilize hexavalent chromium present in the electroplating sludge. The degree of chromium stabilization was evaluated using the Toxicity Characteristic Leaching Procedure (TCLP) Test and Compression Test. The specimens were prepared based on various cr+6 concentration in sludge (12, 6, 1 gr/l) and ASTM C109/C 109M-95 standard. The results show that the Cr contaminated in leaching solution for 12 and 6 g/l Cr+6 in sludge is more than maximum contaminated level (5 mg/l) in TCLP test after 28 days curing but the results of Cr+6 fixation percent show that the mean percent of Cr+6 fixation is 87% and this percent seems to be acceptable for the present situation of electroplating sludge disposal in Iran. Another obtained data showed that the partial replacement of cement with 10% silica fume increase the efficiency of Cr+6 fixation and compensate any negative effects caused by sludge on Cement hydration. It should be mentioned that the Compressive strength amount of all samples are more than the minimum EPA compressive strength for stabilized material (3.5 kg/Cm2).

The water basins of Karaj, Latian, and Lar dams - with an area of 843, 695, and 652 square kilometers, respectively -- include several permanent and seasonal rivers and streams which are the main sources of water supply of Tehran. These basins face serious threats now: all wastes including solid wastes as well as domestic and industrial waste water are the most important threats to the environment, especially to the surface and ground water resources. Unplanned development of cities and residential areas around these resources has caused rapid water pollution, especially from a biological standpoint.The present study also analyzes the contradictory regulations and the overlapping among them which are considered as a threatening factor in these basins.Such parameters as the management of the basins and the role of responsible executive organizations, dealers, and ordinary native people that are among the threatening factors are also studied. Finally, some structural, legal, executive, and managerial points are proposed.

Executed Hydrocarbons contain NO, NO2, PM, SO2 O2, N2, CO, H2O, etc., among which CO2. CO, NO, NO2, PM, and SO2 are known as major environmental pollutants in big industrial cities. In this research, using thermodynamic models for emission prediction, a model is devised for power plant boilers which can predict the CO, NO, SO2 and CO2 concentrations. In the end, a comparison is made between the predicted values and the real ones measured for Tabriz power plant boiler. The results show an acceptable correlation between the predicted and the real figures.

In recent years, researchers and politicians have come to use environmental geopolitics which studies political behavior. Today, the common benefits of states and nations increasingly depend on their cooperation in relation to the protection of the ecosystem of the Earth. In the meantime, due to political, economic, and social characteristics, environmental geopolitics issues display a special image of the countries' common interests. Therefore, in today's world, some nations are interested in and prepared for passing both regional and international environmental laws because it is has been accepted that there is a relationship between environment on the one hand and security, development and national interests on the other hand. Thus, it is better to for the governments to prepare and execute their plans and policies to solve both local and international geopolitics disputes.