JOURNAL OF ENVIRONMENTAL SCIENCE AND TECHNOLOGY
Year:2014 | Volume:16 | Issue:2 (61)|Papers Count:13

Several studies yet have been conducted in the field of climate change in different parts of the world in order to investigate the impact of meteorological parameters changes on the performance of energy sector. In this study، the effect of climate change on the performance of energy generation sector at Iran power plants in next decade has been investigated using the results of climate change calculations in the country’s provinces obtained by downscaling through neural network. Calculations show that the efficiency of gas power plants averagely decreases by 0.6% per 1oC temperature increase. Similarly، the efficiency of steam and combined cycle power plants averagely decreases by 0.5% and 0.4% respectively. Considering the climate change consequences in Iran، the overall temperature will averagely increase about 1.36oC by the year 2025. Conduction a close investigation، the average temperature rise affecting the performance of power plants in the country - which would cause a drop in energy generation sector efficiency - was evaluated to be 1.13oC. After making calculations and utilizing energy and environment software، it was found that the thermal power plants’ fuel consumption will increase about 2.49%. The results revealed that the amount of carbon dioxide emission and social costs caused by emissions will increase by about 1.3% and 2%، respectively.

Biological treatment method is one of the best and most cost-effective methods for the treatment of contaminated wastewaters. The purpose of this study was to evaluate the effect of retention time and temperature on the efficiency of stabilization ponds in removing organic compounds، N-N 3 and PO4 from oil refinery wastewater.Materials and Methods: The method used in the present study was of an experimental type، in which an anaerobic stabilization pond with dimensions of 1×0.2×1 m and a laboratory scale facultative pond with the capacity of 400 L were designed، set up and operated، using fiberglass sheet with a thickness of 6 mm. In this study، the hydraulic retention time of 2 and 5 days for anaerobic pond and 5 and 10 days for facultative pond were set in both hot and cold temperatures. Then، N-NH3 and PO4 parameters were measured at the wavelengths of 425 and 690 nm respectively. Also، TCOD، SCOD، TBOD، SBOD and pH of samples were measured according to the standard methods for water and wastewater tests.Results and Discussion: These results indicated that the retention time and temperature had a significant effect on the efficiency of stabilization ponds، so that the efficiency of anaerobic and facultative stabilization ponds in the removal of organic compounds was significantly increased with the increase of retention time and temperature (p<0.05). The maximum removal efficiency for COD، BOD، N-NH3 and PO4 was obtained to be 93.31، 93.66، 88.15 and 73.17 % respectively (at the retention time of days of anaerobic and 10 days of facultative and hot temperature)، and the minimum removal efficiency for the same parameters was obtained to be 41.47، 40.55، 34.26 and 22.46% respectively (at the retention time of 2 days of anaerobic and 5 days of facultative and hot temperature). Also، the single alga available in the facultative pond was formidiom and it was able to grow in high concentrations of sulfur. The results of this study showed that the pilot-scale stabilization ponds in hot temperature، if operated proprly، have the ability to remove organic compounds with a high efficiency. However، in cold weather، its efficiency is low but in acceptable level.

Iran is located in the dry and semi dry zone of the world and almost 90% of its drinking water requirement is supplied from groundwater resources. Considering the increase of pollution and decline of groundwater resources quality due to agricultural and industrial activities and urban development، this study was conducted to evaluate As، Zn، Cr and Mn concentrations in groundwater resources of Razan plain and to prepare the zoning map during spring and summer in 2012. For this purpose، samples were randomly collected from 20 wells across the plain، and pH and temperature parameters were measured in situ. Concentration of heavy metals in groundwater samples was cited by Atomic Emission device after laboratory preparations. The results showed that the mean concentrations of As، Zn، Cr and Mn in the samples were respectively 5.86±0.69، 30.28±3.42، 0.044±0.005، and 3.69±0.40 ppb in spring and respectively 6.83±0.68، 34.50±3.11، 0.046±0.006 and 4.50±0.51 ppb in summer. Moreover، comparison of heavy metals mean concentrations with WHO permissible limits showed that they were lower than standard levels. The results from comparison of variations in heavy metals mean concentration in two seasons revealed the lack of meaningful difference (p<0.05). The determined correlation between pH، water temperature and heavy metals mean concentration accumulated in the samples indicated no correlation between parameters and heavy metals accumulated concentration. Although the groundwater resources in Razan plain are not currently over polluted with heavy metals، long-term and excessive use of agricultural inputs as well as construction of polluting industries can threaten the groundwater resources of this area in addition to bearing some irretrievable consequences.

Contamination of soil and water with arsenic، which is a toxic and carcinogenic metalloid، can increase the danger of its entrance into the food chain.Material and Methods: In order to improve the efficacy of natural zeoilte for adsorption and stabilization of arsenic in soil، an Iranian zeoilte of clinoptilolite type was modified by iron، manganese and aluminum، and used in a series of chemical extraction tests by DTPA as well as greenhouse experiments using barley as a test crop. Moreover، the biological effects of amending these soil modifiers were evaluated through measuring soil dehydrogenase and phosphatase activity. The experiment carried out in a completely randomized design with Factorial arrangement including 5 types of zeolite (modified with iron، manganese، aluminum، iron+ manganese and iron+ aluminum) and two levels (2% and 5%) of each amendment.Results and discussion: The results of this study revealed that the applied amendments could increase the produced biomass and decrease both arsenic concentration in barely and arsenic extracted by DTPA. Also، further incorporation of amendments increased the activity of dehydrogenase، as a soil health index. However، the iron- and aluminum-modified zeolite was the only amendment which meaningfully increased the phosphatase activity. The reslts indicated that the iron-، manganese- and aluminummodified zeolite can be considered as a good alternative، low cost and environmental friendly amendment for immobilization of arsenic in contaminated soils، and can mitigate the risk associated with arsenic entrance into the food chain.

Introduction: Land application of sewage sludge is one of the most important disposal methods، which allows the sludge nutrients to be used beneficially. However، it should be noted that its pollutants and pathogenic organisms can pose a high risk to the public health and it should be monitored before land application. The aim of this study was to investigate the dried sewage sludge quality from Shahin Shahr WWTPS for its heavy metals concentration.Material and Methods: Samples were collected seasonally from Shahin-Shahr sewage sludge (in three replicates) within 2011-2012، and the concentration of some heavy metals along with microbial and chemical parameters of sludge were measured using DTPA، atomic absorption and standard methods. The results were then compared with the standard levels (EPA) using t-test، and seasonal variations were studied by one way ANOVA and Duncan’s post-hoc test.Results and Discussion: The total and fecal coli forms values did not fall within any standard ranges، so re application of the sewage in the given conditions was restricted due to hygienic precaution. The pH، total solids، organic matter and moisture values were in normal ranges. Seasonal variations of sludge structure showed that the best conditions in terms of absorbable heavy metals concentration lowness belonged to winter. The maximum and minimum annual loads of absorbable concentration belonged to Fe and Cr respectively. Considering the total concentrations، most of the measured elements had the minimum concentration in winter (except for Zn، Pb and Cu) and the maximum concentration in spring and summer (except for As، Zn and Cu). All of the studied metals، except as، and their annual loads (kg/ha/year) had a concentration below the acceptable level. The annual load of as was estimated to be 1.6 kg/ha/year for. Although the annual load of as was below the standard level، it should be taken into account due to being close to this level.

Paint sludge of automotive industries، due to having heavy metals، unbaked polymers، organic and inorganic pollutants، has been classified as a hazardous waste. For this reason، its proper disposal is faced with many problems. Various methods yet have been developed by the great automobile companies of the world to reduce the environmental impacts of paint sludge. One of the effective an economical methods for reduction of pollution is separation of heavy metals from paint sludge. The present study was carried out to investigate the pollution of paint sludge from automotive industry، to reduce its pollution to environmental standard levels، and to recover alumina from the paint sludge through leaching method. After XRD and XRF tests on paint sludge، it was found that the amount of alumina is relatively high. Separation of alumina was considered because of its economic value and various applications in different industries. After utilizing the common separation methods، it was revealed that by optimizing the parameters such as temperature، sludge particle size، and sulfuric acid concentration through the leaching method، about 70% of alumina can be recovered.

Introduction: Implementation of energy auditing in buildings with different applications is one of the issues which has been attracted a considerable attention as a way for saving energy and reducing energy consumption. Auditing in any kind of application، including in residential buildings، needs its own specific methods. Since the technology employed for energy consumption in buildings is different among the countries، to propose a national implementation method it is essential to provide a specific guideline which suits Iran’s conditions.Material and Method: Energy auditing has been performed in different industrial and educational institutes during the last years and it is not a new concept. Moreover، there are some available guidelines for it. The purpose of this paper is to provide a software checklist to enable the users to utilize it step by step in residential buildings energy auditing. This checklist also provides some essential recommendations as outputs based on the data and calculations. Results and Discussion: In fact، the developed software performs calculations for heating، losses، etc. based on the conducted measurements and consequently recommends the most suitable method. Furthermore، to ensure its appropriate performance، the guideline has been applied and tested in a building its energy auditing has been presented.

In order to enhance the efficiency of control plans، reclamation and restoration of destroyed lands and prevention of limited capitals loss are necessary. Absence of a method for covering various criteria and alternatives and proposing the optimal solutions based on a systematic structure and collective view has been always noticed in de-desertification plans. It has been always observed that the alternatives are proposed based on the expert’s partial، nonsystematic and non-holistic view while he or she has no experience in application of systematic models، such as Multiple Attribute Decision Making (MADM)، in de-desertification. Therefore، in this study، the systematic Fuzzy Analytical Hierarchy Process (FAHP) model has been used for proposing optimal solutions to de desertification. In this study، opinions of experts about the priority of criteria and alternatives were assessed by Fuzzy Delphi method and Pirewise comparisons. Then، the final priority of alternatives was obtained by using fuzzy decision making matrix and FAHP model. This model was employed for assessing the efficiency of proposing optimal alternatives in Khezrabad region in Yazd province. According to the obtained results، modification of groundwater withdrawal، with an average weight of 93 ، was identified as the optimal de-desertification alternative in the study area، and other alternatives were found to have an insignificant role in control of desertification.

Introduction: Miankaleh international wetland، located in Mazandaran province، is of high importance in terms of management of water resources and preserving the unique ecosystems and biodiversity. This study attempts to determine the environmental water requirement of Miankaleh wetland.Materials and Methods: Two major sources of water supply for upper basin of Miankaleh wetland، including Siyah Ab and Quz Mahaleh rivers، were chosen to determine the environmental water requirement. First، the duration curve method (hydrological method) was used to determine the environmental flow of the rivers. Then، the comprehensive approach was used to survey the abundance of aquatic bird species population and their dependence on water. Using a combination of these two methods، the environmental water requirement of the wetland was estimated at the estuary of the rivers feeding it.Results and Discussion: The results indicate that، based on duration curve method، the minimum input flows from Siyah Ab and Quz Mahaleh rivers to Miankaleh wetland were 0.578 and 0.054 m3/s respectively. Moreover، considering the aquatic birds in the comprehensive approach، the minimum input flows from Siyah Ab and Quz Mahaleh rivers to the wetland were estimated to be 2.163 and 0.099 m3/s respectively. Miankaleh wetland can be preserved in a good condition (Q75) by maintaining the minimum input flows from to it. Moreover، by maintaining the minimum input flows of about 0.325 and 0.015 m3/s from Siyah Ab and Quz Mahaleh rivers respectively، the wetland is preserved in a relatively good condition (Q90).

Introduction: In this study، a comparative analysis has been made between the environmental laws and regulations related to waste in Iran (as a developing country) and France (as a developed country) to present management solutions using three models of QSPM، SPACE and SWOT.Materials and Methods: In the present study، the two systems were initially identified، assessed and analyzed by comparative analysis، and after the completion of related questionnaires by some of the professors and experts of Environment and Energy Faculty، the data were normalized. Then the superior strategies of SWOT were identified by the QSPM model and employed in presenting management solutions.Results and Discussion: Strategic Position and Action Evaluation (SPACE) matrix showed that Iran laws were in a defensive position and this means that the internal weaknesses must be rectified and the external threats must be avoided. For the effectiveness of management solutions for reducing adverse effects of waste، rectification of the following legal issues should be given priority: enacting Environmental National Policy law، establishing an environmental special commission in the country’s parliament، establishing special courts for environmental crimes، employing Justice Ministry officialexperts to accelerate the settlement of environmental records، amending the law enforcement procedures، motivating and supporting the private sector in recycling the waste from laboratories and hospitals، expediting the preparation of a list of special wastes and providing the necessary legal facilities for reducing the volume of special wastes، and enacting binding legislations for application of up-to-date standards and environmentally friendly technologies.

Excess Ni concentration is considered as a stressful factor for algae، and can affect their growth as a limiting factor. Ni toxicity can also induce oxidative stress in algae and plants by producing free radicals. This study aimed to evaluate the effect of different concentrations of Ni and pH on antioxidant activity، total phenolic and flavonoid contents. Total phenolic and flavonoid contents of extracts were determined by Folin-Ciocaltue assay and expressed based on mg of gallic acid per g of extract. Then the antioxidant activity of ethanolic extracts was assessed by using 2، 2 diphenyl-1- picrylhydrazyl (DPPH). In this study، the highest phenolic content (1873 mg gallic acid/g extarct) and flavonoid content (1106 mg quercetin/g extarct) were obtained at pH=5. In the antioxidant activity test، the maximum IC50 was recorded at pH=9. The results indicated that ethanolic extract of Cladophora glomerata has a noticeable antioxidant ability against various oxidative systems and it can be used as an accessible source of natural antioxidant in food and pharmaceutical industries.

Introduction: The process of economic development and set of economic policies in recent decades have changed the environmental challenges to one of the most important concerns of policy makers. Therefore، investigating the role and impact of the economic policies of the government on environmental quality can be very important.Material and Methods: In this study، the effect of government’s policies on environmental quality in 7 countries of Iran، Syria، Algeria، Egypt، Jordan، Morocco and Tunisia in the Middle East and North of Africa (MENA) during 2007-1997 was investigated in the form of econometric models using panel data. The environmental quality، based on the amount of air pollutants as one of the important indicators of environmental pollution، was studied، and carbon dioxide emission and aerosols concentration were considered as the variables indicative of air pollution.Results and discussion: The results show that depending on the type of index selected for the environmental quality، government’s economic policies can have a direct and positive relationship with air pollutants. Indeed، the findings emphasize that investment of government is an important and influential variable in determining the amount of carbon dioxide emissions in the studied countries، and has put a positive impact on increase of carbon dioxide emissions. However، this result is not confirmed in the case of aerosols.