JOURNAL OF ENVIRONMENTAL SCIENCE AND TECHNOLOGY
Year:2009 | Volume:10 | Issue:4 (SPECIAL ISSUS 39)|Papers Count:16

Biosorption of heavy metals can be an effective process for the removal of heavy metal ions from aqueous solutions. In this study, the removal of Pb (II) and Zn (II) by dead cells of a lignolytic whiterotfungs, Phanerochaete chrysosporium, was investigated. In addition, the effect of pretreatment of P.chrysosporium biomass on biosorption of Pb (II) and Zn (II) was studied. Pretreated P.chrysosoporium has been used for biosorption of metals in this study. Here, the adsorption technique has been done in Batch system. The effects of the initial metal ion concentration, initial pH, stirring speed and contact time on biosorption efficiency were studied. The surface change density of thebiosorbents varied with the pH of the medium and the maximum biosorption of heavy metal ions on the biosorbents was obtained between Ph 5 and 6.The Biosorption of Pb (II) and Zn (II) on the biosorbents increased as the initial concentration of Pb (II) and Zn (II) ions were increased in the medium. Biosorption equilibrium was established about 1 h, the adsorbed heavy metal ion did not significantly change further with time. The maximum heavy metal ions adsorbed was found to be 90 and 63 mg/g dry biomass P.chrysosporium for Pb (II) and Zn (II), respectively.The results indicated that increasing the temperature led to an increase in the adsorption rate. The experimental adsorption data were fitted to the Langmuir and Freundlich adsorption models. The affinity order of heavy metal ions showed Pb (II)>Zn (II). The biomass was regenerated by washing with a 50 mM solution of HCI. The desorption efficiency was as high as 98%. The results suggested that P.chrysosporium could be used as a biosorbent for an efficient removal of heacy metal ions from aqueous solution.

Own-ebne-Ali Forest Park which is located in the north of Tabriz provides a variety of important environmental services for the benefit of present and future generations. These services have economic values that are often hard to quantify in terms of general criteria because they do not produce any revenue directly. However, they provide benefits in terms of the quality of life and recreational opportunities and their economic value can be estimated mainly via some indicators.In this study, Clawson method was used for the estimation of the social and economic values of Ownebne- Ali Park. This method was based on using the maps, preferences and social and economic characteristics of the visitors and the relationship between the cost of access to the park and the number of visitors. Then, the demand curve was drawn based on the data obtained by questionnaires. Calculations suggested the daily recreational-economic value of the park to be 125081000 Rials.The results of the study also indicated that most visitors of Own-ebne-Ali Forest Park were in the age range of 20-30 years. Some 40% of the visitors had a diploma, as their minimum educational degree, and 31.9% of them had a monthly income of 1-2 million Rials.

Adsorption is one of the most effective processes in the final treatment of water for the removal of organic matters and heavy metals. In the present study, the use of three carbonaceous materials, i. e., Granular Activated Carbon (GAC), Almond Shell Charcoal (ASC) and Walnut Shell Charcoal (WSC), were investigated as adsorbents for the removal of phenol from contaminated water. Batch experiments were carried out to obtain the best adsorption conditions. The correlation coefficients in Freundlich and Langmuir isotherms turned out to be .99 and .99 for GAC, .92 and .96 for ASC, and .93 and .95 for WSC. Maximum removal of phenol from contaminated water by GAC, ASC, and WSC was 99.87%, 91.36%, and 78.17%, respectively.

This research studies the factors affecting special organizational evolution of Lavasan and Sharifabad cities from the 1970s up to the present time based on geographical structuralism school, the political economic viewpoint of space, and the theory of rantier economy and state. Studies have shown that the nature of socio-economic system dominant in Tehran has deep and extensive effect on production and special formation of this city and its neighboring villages and cities. Moreover, the performance pattern of planning and management of civic and regional development originates from this in dangerous and exogenous socio-economic structure. This structure is one of the oil income versions that has shown its effects on special development of Iran and metropolitan Tehran and its periphery specially Lavasan and Sharifabad. The results and effects of imbalance and domination of Tehran with its periphery special units from the recent decades and unorganized, scattered, and without program trend of Tehran civic development has caused the process of changing villages to cities to continue and these units to encounter several socio-economic, population, physical, and environmental problems. Among these factors, the habitats of the peripheral region, under the effect of the role and performance of Tehran, have faced with different structural and functional evolution developments, each of which regarding its natural environmental, social, economic, and physical conditions has caused a special spatial structure (as in Lavasan and Sharifabad.

In this research, the adsorption of Cr (VI) ions on rice bran has been studied using batch adsorption techniques. The main objectives of this study are 1) to investigate the chromium adsorption from aqueous solution by rice bran, 2) to study the effect of experimental conditions -such as pH, contact time and initial chromium concentration- on adsorption process performance and 3) to determine appropriate adsorption isotherm and kinetics parameters of Cr (VI) adsorption on rice bran.The results showed that adsorption of chromium by rice bran reached equilibrium after 120 minutes and following this time a little change was observed in the efficiency of chromium removal. Higher chromium adsorption was observed in lower pHs and maximum chromium removal (99.8%) was obtained in the pH of 2 for an initial concentration of 5 mg/l. Adsorption decreased with an increase in the initial chromium concentration. The obtained results also revealed that among 6 studied isotherm models (Langmuir, Freundlich, BET, Temkin, D-R and generalized adsorption models), the adsorption of chromium (VI) by rice bran followed Frendlich isotherm equation with a correlation coefficient of 0.997. The maximum monolayer adsorption capacity was determined to be 0.208 mg/g for the experimental conditions of the present study. In addition, the kinetic order of the adsorption of chromium by the studied adsorbent follows a pseudo-first order rate with a high correlation factor (R2³0.99) at 25oC. The results indicate that rice bran can be used as a lowcost alternative to commercial adsorbents in the removal of Cr (VI) from water and wastewater.

In this research, the performance of three chemical compounds (Ferro sulfate, ferric chloride and calcium hypochlorite) and the effect of an increase of TDS on them in sulfide removal have been studied.The results showed that using these three chemical materials, chemical precipitation was a proper method for effluent treatment. With the change of pH from 4 to 9 under the concentration limit of sulfide 0.95-47.05 mg/l and following the study of 97 effluent samples, the highest sulfide removal efficiency of nearly 61.38-66.21% was observed in a pH of 7. Besides, after checking 59 effluent samples, Ferro sulfate with the concentration of 2-100 mg/l under the concentration limit of sulfide 0.95-47.05 mg/l had the highest sulfide removal efficiency of about 55.79-73.94%. Moreover, after studying 62 effluent samples, Ferric chloride with the concentration of 2-100 mg/l under the concentration limit of sulfide 0.95-47.05 mg/l had the sulfide removal efficiency of nearly 67.5-84.2%. Furthermore, Calcium hypochlorite with the concentration 10-500 mg/l under the concentration limit of sulfide (0.95-47.05 mg/l) and with checking 60 effluent samples had the sulfide removal efficiency of about 62.17-80.85%. It can be seen that the ratios of ferric, Ferro and hypochlorite ions to the sulfide ion are 2, 5 and 10, respectively and that Ferric chloride has the highest removal efficiency with less concentration. Finally, the results have shown that the decrease in the removal percentages of Ferro sulfate, Ferric chloride and Calcium hypochlorite by increasing TDS to 1000 mg/l was not significant while with the increase of TDS up to 1500 mg/l, sulfide removal efficiency is considerable.

In this research, the olefin plant of Bandar-e-Imam Petrochemical Complex was studied in terms of environmental problems. Waste water, air pollutants, noise pollution and solid wastes were recognized as the sources of pollution. Then, the sampling sites were chosen, the quality parameters were defined for the waste water and air pollutants, and the samples were taken over a period of 6 months.The results of the study show that the concentration of COD, OIL, TDS parameters and of the phosphate ion in the waste water of the olefin plant were much higher than the national standards.The estimation of the pollution load for the mentioned parameters also confirmed this finding. The amounts of atmospheric pollutants (CO, NOX and SO2) in the studied plant were found to be within the range allowed by the Environmental Protection Organization. Hydro carbonic vapors (HCVs) were among the other pollutants at the plant. The study of noise pollutants showed that the highest balance of noise pressure in the olefin plant was 102 dB (A). Moreover, 14 types of solid waste were identified, of which 10 (constituting 84% of the total solid wastes) were found to be hazardous.

Nowadays, wastes are known as environmental pollutants which can threaten people’s health if we don’t try to reduce them. Landfills play an important role in the network of solid waste disposal, and therefore, are considered an integral part of the new strategy of integrated solid waste management. In recent years, the design of a landfill has included the equipment for the control and transmission of gas and the use of energy of biogas.The landfill gas (LFG) is obtained through a number of bio-chemical reactions on degradable organic compounds in anaerobic conditions. These gases include methane, carbon dioxide, hydrogen, hydrogen sulfide, volatile organic compounds, and so on. The assessment of gas generation rate and its emission from the landfill is of great importance in designing such sites and the successful use of the produced gases as sources of energy. After extraction and treatment, gases generated in the landfill are used for the production of the energy needed in industry.In this study, the emission of gases and pollutants from Shiraz landfill is investigated using the software package of "Land GEM" Sensitivity analysis with different values for k (rate of degradation) was conducted on them. The results showed that the amounts of methane and carbon dioxide were 1.5×106 m3/y and 9.6×105 m3/y, respectively. Besides, the highest quantity of methane generation is estimated for the solar year of 1400.

The neutrality of living spaces in the urban environment and man’s lack of space in the urban structure both indicate that contemporary man is suffering from homelessness and lack of space. That is why citizens and urban dwellers have lost their identity and their interaction with the environment. The mission of urban planning is to enhance urban spaces to places in which social and human values can be manifested.Phenomenology has the potential to create meaningful environments and call for a sense of place, spirit of place, and meaning of place, all of which being the basic elements of the identity of a place. The results of the present study have shown that it is not needed to look for a new designing style, instead, it is necessary to search for traditional meanings and values in the architecture and construction of cities with especial attention to phenomenological approach.

Since the establishment of Green Management System in various organizations is one of the government’s priorities and due to the importance of Green Management for a decrease in the consumption of resources such as water, energy, paper and waste management, the implementation of this system in the National Library of Iran is a necessary issue, which is studied in the present paper. First, the goals were defined and the framework for the correct management of resources consumption (Green Management) was specified. Then, the consumption of resources at the National Library was studied so that managerial solutions could be offered. To this end, the library was visited several times, certain checklists and questionnaires were completed, and the necessary data were collected and analyzed.The obtained results regarding the fuel energy consumed by transportation in the National Library show that among the generated pollutants (CO2, CO, NOx and hydrocarbons), CO2 has the highest rate (904 Kg). CO (6 Kg), NOx (2 Kg) and hydrocarbons (0.58 Kg) are in the next ranks. Among energy-consuming equipment and appliances, refrigerators produce the highest amount of CO2, SO2 and Nox. The CO2 produced by all of them amounts to 1140.32 Kg; the figures for SO2 and NOx are 3.9072 Kg and 2.886 Kg, respectively.As to the consumption of water, the results show that the total amount of water consumed by the library is as much as 45459 L/Y, most of which (32471 L/Y) is used for the irrigation of green space. Regarding wastes, 30 times of sampling revealed that most of them were aluminum and paper wastes. The amounts of CO2, SO2, NOx and particles were 19475 Kg, 77.54 Kg, 57.4 Kg, and 2.92 Kg, respectively.Finally, it has been made clear that the Green Management can help optimize the use of resources and reduce the costs.

On average, 72,559 Kg of wastes is collected daily from medical centers and hospitals in the city of Tehran. A thorough qualitative and quantitative assessment of such wastes can help improve the current hospital waste management practices.In the present research, twenty private hospitals in Tehran have been studied over a period of four months. The data-collection instrument was a questionnaire comprising items concerning the number of wards and occupied beds, and the amount of general and hazardous wastes of each ward. The sample wastes taken from selected wards were weighed. The average waste production rate turned out to be 8,430 kg per day. Given the 2,475 beds in the hospitals under study, 3.406 kg of wastes per bed is generated daily. Surgery and emergency wards generate the highest amounts of infectious waste per day -2 and 1.8 kg per bed, respectively. The lowest amount is that of the children’s ward with 0.25 kg per bed each day. Gynecology and children’s wards generate the highest daily amounts of general waste (3 and 2.5 kg per bed, respectively). The total amount of wastes generated was found to comprise 60% of general wastes, 39% infectious wastes and 1% of sharp wastes. Improper waste separation has led to relatively higher amounts of infectious wastes. Encouragement and training of hospital staff and improvement in collection and transportation processes by Tehran Municipality are the key to successful hospital waste management.

Due to their suitable strength against mechanical impacts and also their economic advantage as compared with other packaging materials, polymeric products are increasingly used in different industries. One of the problems with the use of plastic materials is that their non-decomposition may have negative effects on the environment. One of the aims of the present study is to find an economical method for recycling plastic packaging materials and to change them into isolators with a higher added value than traditional recycling methods.In this research, the samples were prepared from PET and PP packaging materials; the mesh sizes were 1 to 5 mm and 6 to 20 mm with equal weights. The researcher used polyester fibers (2.5% of the total weight of the polymeric materials). They also applied polyvinyl acetate (20 % of the weight of the polymers) as the composite binder. To prepare the final mixture, the mentioned materials were mixed at three stages and molded three times.After being prepared, the samples were tested with INSTRON device at the speed of 20 mm / min. The researchers measured the compressive strength of PET and polyester fiber samples, of samples produced from PET and PP combined, and of polyester fibers with 1 to 5 mm particle mesh size. The results indicated that the mean variation of sample length due to compression in 10, 20, 30, 40 mm of PET and polyester fiber samples required 1.2, 10.8, 18.6, 31.9% more pressing force load compared with the sample produced from PET and PP. Meanwhile, the compressive force of PET was compared with that of polyester fiber samples with PET and PP and polyester fibers combined with 6-to-20-mm particles mesh size. The findings showed that in length variation of 20, 30, and 40 mm, samples made with PET and PP needed more load force (4.5, 14, 25.3%) compared with PET and polyester fibers made with PET angiopolyester fibers. Also, the results of the t-test for a comparison of means showed that the mean difference with a=0.05 for samples made with PET and PP combined in 10,20,30 and 40 m variation in the length of two-groups samples wass significant.

In GTL process -the conversion of gas to liquid products- a great amount of energy is released.Meanwhile, the various warm and cool streams in this process with their significant temperature difference can internally supply the required energy of the system. In fact, the GTL process has the potential to produce a considerable amount of energy far beyond its needs. The excess energy is so much that it can even run a power plant. In other words, the process of converting natural gas to liquid hydrocarbons not only is self-sufficient from an energy point of the view, but also can produce energy.In this paper, various approaches to energy optimization in a GTL unit with a capacity of 10, 000 BPD are studied using optimizer software at different stages of the process. Then, the most suitable method is selected and the amount of the generated energy is calculated and reported. Finally, an integrated network of heat exchangers is suggested.