Mohsen Azizi; Abbas Khashei; Mehdi Dastorani
Abstract
Background & objective: Today, the pollution caused by landfills is considered as one the serious environmental threats, including groundwater resources. The purpose of this research, the use of mathematical models and numerical with high precision in determining and explaining the current situation ...
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Background & objective: Today, the pollution caused by landfills is considered as one the serious environmental threats, including groundwater resources. The purpose of this research, the use of mathematical models and numerical with high precision in determining and explaining the current situation and relatively accurate predictions, to examine the groundwater pollution caused by leakage of leachate centers around landfill. Materials & Methods: In this research, The MODFLOW, MODPATH and MT3DMS models was used to estimate the speed of movement of pollution, tracing path and simulate the process of transfer of leachate producedat San Angelo landfill site in the United States to the downstream drinking water well. Also Three scenarios of a) improved bedding of landfill bottom and reduced leachate penetration to 25%; b) Reducing the amount of extraction downstream drinking water well to 20%; c) landfill Movement as much as 100m to upstream were evaluated. Results: The results of the modeling showed that in the current situation, the leachate produced landfill reaches the downstream well going through a distance of 608 meters in 2158 days. By applying three scenarios in the numerical model was seen that the leachate reaches to the downstream well by passing a distance of 613, 618, and 667 m in 4000, 3250 and 4000 days, respectively. Conclusion: Therefore, in the field of locating the landfill and leakage of leachateto groundwater, numerical models can be used to predict the direction and speed of pollution movement and to make management decisions for reducing the time and distance of arriving the pollution at the groundwater.
Javad Torkashvand; Mahdi Farzadkia; Ahmad Jonidi Jafari; Mohsen Heidari; Ahmad Ghalkhanbaz
Abstract
Background and Aims: There are various methods for the disinfection of infectious wastes which are of great importance due to their potential health and environmental risks and there are different insights about their management in Iran. Hence, the aim of this study was to survey the various aspects ...
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Background and Aims: There are various methods for the disinfection of infectious wastes which are of great importance due to their potential health and environmental risks and there are different insights about their management in Iran. Hence, the aim of this study was to survey the various aspects of disinfection methods of infectious waste on the basis of environmental health specialist insights. Material and Methods: For performing this study, a questionnaire was prepared and the opinions of the specialists were gathered about five disinfection and disposal methods of infectious wastes, and finally the data were analyzed. Moreover, the preferences of the specialists for selecting each method were also asked based on 9 various aspects. Results: It was found that health issues received the highest priority (with 26% of desirability) from the specialists in selecting the method, while the lowest priority was assigned for financial issues (with 8% of desirability) and political acceptability (with 6% of desirability). Environmental health specialists believed that autoclaving and waste incinerating with 77.8% and 44.1% of desirability, respectively, are the most favorable and undesirable methods for disinfecting the infectious wastes. The results showed that the disinfection is a top priority for the specialists, and, with respect to current situation, they did not make any significant difference between on-site and ex-situ disinfecting methods, which is reflected in the scores of 3.65 and 3.72 for these two scenarios. Conclusion: Overall, health aspects have the most important priority in the management of infectious wastes. Therefore, autoclaving and microwaving are the most appropriate methods for the disinfection of such wastes. Landfilling and incineration were not suggested for the disposal or treatment of infectious wastes.
Arezoo Khalijian; Soheil Sobhanardakani; Mehrdad Cheraghi
Abstract
Background & Objective: Increasing population growth, and therefore, increasing requirements for development of the agricultural productions, lead to be overused the pesticides. So, their residues in environment, particularly surface and groundwater resources, create human health risks. Therefore ...
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Background & Objective: Increasing population growth, and therefore, increasing requirements for development of the agricultural productions, lead to be overused the pesticides. So, their residues in environment, particularly surface and groundwater resources, create human health risks. Therefore due to the serious risk to human health, this study was carried out for assessing the diazinon residues in groundwater samples of Hamedan-Bahar Plain in 2014. Material and Methods: Water samples were collected from 20 stations along the Hamedan-Bahar Plain in summer 2014. After preparation and processing the samples in the laboratory according to liquid phase extraction, diazinon residues in samples were determined using a spectrophotometric method in three replications. All statistical analyses were performed by SPSS 20 software using Kolmogrov-Smirnov, one-way ANOVA, One Sample T Test and Pearson's Correlation Coefficient. Results:The results showed that the mean concentration of diazinon residues in samples was 0.23±0.06 µg/mL-1, being upper than the Maximum Contaminant Levels (MCLs) provided by the WHO. Conclusion:Since based on WHO guideline the mean concentrations of diazinon residues in groundwater resources of Hamedan-Bahar Plain were upper than MCLs, therefore; exploitation of water for drinking has adverse effect on consumers' health. In this regards, concerning increased use of agricultural inputs especially pesticides, regular periodic monitoring of chemical pollutants content in groundwater resources of study area is recommended.
Saeed Motesaddizarandi; Rasul Nasiri
Abstract
Background and Aim: Tehran, as the largest and most populous city in Iran, has encountered many problems, of which air pollution is the most common. In recent years, PM2.5 has been the cause of the unhealthiest days in terms of air pollution in Tehran; For this purpose, the present study was conducted ...
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Background and Aim: Tehran, as the largest and most populous city in Iran, has encountered many problems, of which air pollution is the most common. In recent years, PM2.5 has been the cause of the unhealthiest days in terms of air pollution in Tehran; For this purpose, the present study was conducted with the aim of Spatio-temporal analysis of PM2.5 pollutant in the Tehran metropolis during the years 2014-2017 using GIS. Materials and Methods: In this study, Inverse Distance Weighting (IDW) and HotSpots methods have been used to predict and zoning of PM2.5 concentrations during four consecutive years (2014-2017). Results: The results of hotspot analysis and Getis-Ord-Gi index showed that the southern and southwestern regions with a confidence level above 90% and a concentration of more than 50 μg/m3 are the most polluted areas. And to a lesser extent, the western and central areas are next.; Also, the concentration of PM2.5 pollutants shows an increasing trend from north to south and east to west. Conclusion: South, southwest, west, and center are the most polluted areas; However, the present study only shows the zoning of PM2.5 concentration and does not identify the various factors and the contribution of each of them in the production of this pollutant; And it is necessary to conduct studies to identify sources and their contribution to control and reduce the concentration of PM2.5 in the Tehran metropolitan.
Mohammad Ebrahim Fazel Valipour
Abstract
AbstractBackground and Aim: Heavy metals contamination of soils is one of the main environmental problems. Heavy metals are considered as one most dangerous groups of pollutants because of their toxicity and stability. The biological and ecological importance of heavy metals is due to their characteristics ...
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AbstractBackground and Aim: Heavy metals contamination of soils is one of the main environmental problems. Heavy metals are considered as one most dangerous groups of pollutants because of their toxicity and stability. The biological and ecological importance of heavy metals is due to their characteristics of polluting, their toxicity, persistence and bioaccumulation. The aim of this study was to investigate the spatial distribution of heavy metals in region Dehnow Shandiz (North West of mashhad).Materials and Methods: In the present study, 20 soil samples (10-30 cm depth) collected and total concentration of As, Cd, Co, Cr and Ni were measured using Atomic absorption spectrophotometer device. Also, some other soil properties including PH, Organic carbon, CEC and soil texture proportions were measured.Results: The results showed that the average concentrations of As, Cd, Co, Cr and Ni in the study area were 10.87, 0.26, 14.8, 56.6 and 68.2 mg/kg respectively. Also the results of statistical analysis showed that the standard deviations of As, Cd, Co, Cr and Ni in the study area were 1.97, 0.16, 1.32, 19.47 and 17.39 respectively.Conclusion: The results indicate that the average concentration of Ni in the soil of study area were higher than the standard of the Environmental Protection Organization of Iran and As, Cd, Co and Cr were lower than the standard. The presence of serpentinite soils has increased the concentration of nickel in the region.Document Type: Research article
Mojgan Mirzaei; Eisa solgi
Abstract
Background and objective: Emission of pollutants caused by natural and human activities on the environment is one of the most important issues in today's society. Objective: This study was based on laboratory studies, field and review of the literature. The aim of this study to determine the concentration ...
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Background and objective: Emission of pollutants caused by natural and human activities on the environment is one of the most important issues in today's society. Objective: This study was based on laboratory studies, field and review of the literature. The aim of this study to determine the concentration of heavy metals (cadmium, copper, manganese, nickel, lead and zinc) in the sediment of Zayandehrood river sediments and comparing them at different stations and various seasons from early October 2014 until late September 2015. Materials & Methods: ICP-AES techniques were used to determine the concentrations of heavy metals by atomic absorption spectrophotometer and then the emissions of metals evaluated with statistical software and Mueller indicator. Zayanderood basin is located in 50° 2´ to 53° 24´ east longitude and 31° 12´ to 33° 42´ north latitude. Results: The results showed high levels of cadmium concentration in Vahid Bridge station in the summer with the amount of 0.0081 ± 0.95, milligrams per kilogram of dry weight that is higher than Canada and New York sediment quality standard. Conclusion:The results showed high levels of cadmium and further concentration of global standards for electroplating industry and agricultural activities in upstream stations. High levels of manganese and lead in Chum Bridge and Varzaneh are related to agricultural activities mainly. Generally, Vahid Bridge station has more unsuitable situation than the other stations.
Shahrokh Nazmara; fatemeh eslami; mehdi salari; Alireza beheshti; Mohsen Yazdani avval
Abstract
Background & objective: People commonly spend, on average, 5-6% of their time in a day in enclosed vehicles. Smoking in vehicles with little volume can result in potential harmful effects on children and other passengers. This study aimed to evaluate the concentrations of suspended particles produced ...
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Background & objective: People commonly spend, on average, 5-6% of their time in a day in enclosed vehicles. Smoking in vehicles with little volume can result in potential harmful effects on children and other passengers. This study aimed to evaluate the concentrations of suspended particles produced from smoking and the exposer time of passengers to the produced smoke. Materials & Methods: This cross–sectional study was performed in Tehran, 2014. The exposure to cigarette smoke was measured using Grimm11-A device that had 16 entrances with different sizes from 0.3 to 20 µm. The studied vehicle was Pejo 405 , andwindows condition were as following: 1 back window open, 2 back windows open, 1 front window open, 2 front windows open, 2 front and 1 back windows open, 4 windows open and 4 windows close. SPSS 16 software was used to make statistical analysis ( one-way ANOVA (p<0/05)). Results: Numerical concentrations of particles in small size row (PM2.5) were several LOGs higher than larger sizes row. In addition, it was observed that exposure time to particles in small size row had significant difference with large size row. The maximum exposure concentrations with a p-value<0.05, and the maximum exposure time with a p-valueConclusion: According to the gained results, the largest portion of cigarette smoke particles in vehicles belonged to the PM2.5. Different conditions of windows in their opened and closed states can be effective on ventilation. So that the more numbers of windows are opened the greater ventilation will occure. Generally, because of the limit space of vehicles and high exposure concentrations, the enactment of cigarette smoking prohibition legislation seems to be necessary.
Hossein Alidadi; Seyedeh Blin Tavakoli Sani; Batoul Zarif gharaati oftadeh; Mohammad Tafaghodi; Seyed Hossein Shams Zadeh; Maryam Fakhari; Ali Asghar Navaei Fezabady; Mohsen Yazdani
Abstract
Background and objectives: Corrosion and Scaling in distribution network pipes is one of the most important indices in water quality evaluation and one of the most common environmental phenomena that deteriorate water quality, color, odor, taste and also increases the concentration of heavy metals in ...
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Background and objectives: Corrosion and Scaling in distribution network pipes is one of the most important indices in water quality evaluation and one of the most common environmental phenomena that deteriorate water quality, color, odor, taste and also increases the concentration of heavy metals in water. Corrosion causes entry of bye-products to water and decreases pipe life and sedimentation, reduces the flow rate and the efficiency of valves and fittings. The purpose of this study was to determine the corrosion or Scaling state of drinking water in Mashhad in 2017. Material and methods: In this study, 72 samples were taken during 2017 to evaluate water quality characteristics, and analyzed based on the standard methods. Then, three indices including Langlier, Ryznar and Aggressiveness Indices were programmed in Excel software and based on this, Corrosion and scaling potential of drinking water were determined. Results: Results showed that the averages of Langlier, Ryznar and Aggressiveness Indices for water were 0.14±0.48, 6.67±0.38 and 12.23±0.23, respectively. According to the Langlier and Ryznar indices, 86.1% of total samples had low scaling potential and according to Aggressive index 97.2% of total samples had scaling. Also, the results showed that 58.33% of the samples were low scaling in spring and other samples were high scaling. In addition, in the summer, 33.3% of the total samples were high scaling and other samples were low scaling. Conclusion: The results showed that drinking water of Mashhad city was Scaling. Therefore, it is necessary to take measures to control scaling in distribution network pipes, especially in areas located in high scaling zones.
hossein kamani; ayat hossein panahi; Somayeh Talebi; mohamad havangi
Abstract
Background and Objectives: Phenol is one of most common organic pollutants in aqueous environments. Phenol presence in the environment can make some health problems such as carcinogenesis, abnormality of heartbeat, etc for humans and poisonous problems for other organisms. Therefore, this pollutant must ...
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Background and Objectives: Phenol is one of most common organic pollutants in aqueous environments. Phenol presence in the environment can make some health problems such as carcinogenesis, abnormality of heartbeat, etc for humans and poisonous problems for other organisms. Therefore, this pollutant must be removed from polluted effluents to prevent water pollution. Using nanoparticles in adsorption processes is considered as an effective method for contaminants removal. The aim of this study was to investigate the efficiency of magnesium oxide nanoparticles in phenol removal from aqueous solutions. Materials and Methods:In this research, nanoparticles of magnesium oxide were used with size of 43 nm. After the preparation of phenol stock solution, effects of pH،(3- 5- 7- 9- 11)، contact time(10,30, 60, 90, and 120 min)، MgO dosage(20, 40, 60, 80 and 100 mg/L) and initial concentration of phenol (25, 50, 75 and 100 mg/l) Were investigated. Results: Results indicated that the removal efficiency increased with increasing pH, contact time, MgO dosage to a certain range and decreasing initial concentration. Such that the maximum efficiency was equal to 81% in the pH of about 11, initial concentration of 50 mg/L, MgO dosage of 80 mg/l and contact time of 60 min. It was found that adsorption kinetics and equilibrium data follow a pseudo-second-order kinetics model and a Langmuir isotherm model respectively. Conclusion: This study showed that the magnesium oxide nanoparticles have the ability to remove the phenol and can be used effectively in removing phenol from aqueous solution
Sima Zamand; Hossein Alidadi; Abolfazl Naimabadi; Vahid Taghavimanesh
Abstract
Background and Aim: : Produced wastewater by various industries is a dangerous and considerable pollution resource for the environment. The presence of non-biodegradable dyes in effluents of dying industries is regarded as a major problem. The purpose of this study was to evaluate the efficiency of electro-fenton ...
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Background and Aim: : Produced wastewater by various industries is a dangerous and considerable pollution resource for the environment. The presence of non-biodegradable dyes in effluents of dying industries is regarded as a major problem. The purpose of this study was to evaluate the efficiency of electro-fenton process in dye removal from the wastewater of dying industries. Materials and methods: : In the present experimental study conducted in 2017, wastewater sampling was performed according to the Standard Methods for the Examination of Water and Wastewater. The samples were transferred to the electrochemical cell reactor and the effect of different parameters such as applied voltage, iron concentration, pH, and reaction time on dye removal efficiency were investigated. Results: According to the results, optimum conditions of Electro-Fenton process in dye removal was determined. Accordingly, in applied voltages of 25 and 35 V in 100 and more than 200 mg/L dye concentrations, , reaction time of 50 - 60 minutes, Fe2+ concentration of 0.3 mg/L and pH of 3 the dye removal efficiency of 99.8 % was achieved. Conclusion: The electro-fenton process is able to remove dye with different concentrations and maximum efficiency. Based on the results, the applied voltage and the concentration of Fe2+ were the parameters that are more efficient and pH along with reaction time demonstrated less impact on the efficiency of the electro-fenton process in dye removal from industrial wastewater.
Mersedeh Sadat Hozhabralsadat; Ava Heidari; Zahra Karimian; Mohammad Farzam
Abstract
Abstract Background and Aim: Today, air pollution, with an impact on a global scale, is an important concern of the modern world. It has many adverse effects on human health and the environment. Therefore, it is necessary to find sustainable and environment-friendly solutions that prevent the increase ...
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Abstract Background and Aim: Today, air pollution, with an impact on a global scale, is an important concern of the modern world. It has many adverse effects on human health and the environment. Therefore, it is necessary to find sustainable and environment-friendly solutions that prevent the increase of pollution levels and help eliminate them. One of the newest ways to reduce air pollution and absorb particulate matter, as well as improve air quality, is to use green walls in urban spaces. The present study investigated the potential of green walls in reducing air pollutants. Materials and methodology: In this research, two green walls were installed at the Khayyam intersection in Mashhad for three months. Finally, the Air Pollution Tolerance Index was determined for all the plants by measuring chlorophyll, ascorbic acid, leaf-related water content, and pH. Results All of the plant species planted on the walls were classified as intermediate in the tolerance. Among all the plants, Carpobrotus edulis and Rosmarinus officinalis had higher APTI, which makes them more resistant and suitable for planting in polluted areas. Considering the statistical analysis, the APTI of the plants was correlated with ascorbic acid and leaf-related water content. Conclusion: Our findings suggest the suitability of the above-mentioned plants for plantation in areas with high levels of pollutants.
Mohsen Mohammadi; Ali Akbar Hedayati; Mohammad Forouhar Vajargah; Ahmad Reza Pirali; Maryam Fallah
Abstract
Background and Aim: Sediment monitoring in aquatic environments is very important due to long-term exposure of various pollutants. This study was conducted to monitor the pollution of some heavy metals (Cd, Cu, Fe, Pb and Zn) in the surface sediments of Anzali wetland.Materials and Methods: For this ...
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Background and Aim: Sediment monitoring in aquatic environments is very important due to long-term exposure of various pollutants. This study was conducted to monitor the pollution of some heavy metals (Cd, Cu, Fe, Pb and Zn) in the surface sediments of Anzali wetland.Materials and Methods: For this purpose, sediment samples were collected from east, west and central parts of the wetland in different seasons of 2020. Heavy metals contamination zoning for sediments in the study area was performed using Arc GIS 10.7Results: The results showed that the highest level of contaminants were obtained in the western part of the wetland. The average concentrations of heavy metals in the sediments were related to Cu (18.47), Zn (74.15), Cd (0.67), Pb (12.05) and Fe (1.97) mg. kg-1 in the western part. The pattern of changes of studied metals was in conformity with Cd 0.05) between Pb, Cu and Zn. According to the zoning map of the parts located in the middle of the center to the west of the wetland, higher amounts of metals have been deposited in its sediments.Conclusion: In general, various human activities and the development of industries and the existence of agricultural lands in the area of Anzali Wetland and incoming rivers can be considered as factors affecting pollution. Therefore, with continuous biological and ecological monitoring of the wetland, it is possible to estimate the amount of heavy metals and the share of each in the wetland. Also, management in order to protect and monitor the wetland seems necessary.
Laleh Roomiani; Mahsa Mostofipour
Abstract
Background and purpose: Nitrate is used as a chemical water quality indicator. The aim of this work was investigation of nitrate adsorption from aqueous solution by Nanocomposite celloluse/Fe3O4/ZnO as a efficient adsorption.
Materials and methods: This study was conducted in a laboratory batch reactor. ...
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Background and purpose: Nitrate is used as a chemical water quality indicator. The aim of this work was investigation of nitrate adsorption from aqueous solution by Nanocomposite celloluse/Fe3O4/ZnO as a efficient adsorption.
Materials and methods: This study was conducted in a laboratory batch reactor. The most important variables affecting adsorption process were pH (2, 4, 6, 8, 10), time (25, 50, 75, 100, 125, 150, 175, 200, 250, 300 min), nitrate concentration (0, 50, 100, 150, 200, 250 mg/L), adsorption dose (0, 2, 4, 6, 8, 10 g/ L), Mixing speed (0, 50, 100, 150, 200 r/ min) investigated and adsorption kinetic and isotherms were determinated. Spectrophotometer was used for nitrate measurement and adsorbent characteristics were determined by SEM and FTIR examinations
Results: The results showed the optimum pH=6 and nitrate adsorption increased by increasing contact time and adsorbent dosage. The adsorbent specific surfact area of 10 m2/g was obtained and FTIR test revealed the finctional groups existing on adsorbent surface to have important role in nitrate adsorption. Experimental data was well fitted by pseudo second-order kinetic model. Langmuir isotherm model best represented the experimental data to describe adsorption.
Conclusion: Results showed that the nanocomposite cellulose/Fe3O4/ZnO can efficiently remove nitrate from aqueous solution
Fatah GHangi Zadeh; Abdolreza Karbassi; Naser Mehrdadi
Abstract
Background and Purpose: Benzene is one of the primary volatile organic compounds in urban air pollution. Beside its environmental implications, benzene poses various health risks to urban inhabitants. This study aimed to measure benzene levels at fuel stations (petrol pumps) in a specific area of Tehran ...
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Background and Purpose: Benzene is one of the primary volatile organic compounds in urban air pollution. Beside its environmental implications, benzene poses various health risks to urban inhabitants. This study aimed to measure benzene levels at fuel stations (petrol pumps) in a specific area of Tehran and model its dispersion to determine safe distances from the release point. Materials and Methods: The study, assessed benzene pollutant concentrations at 11 selected gas stations in Tehran’s 4th district over one-year using gas chromatography with a GC-FID flame ionization detector. Additionally, pollution dispersion modeling was conducted using the AEROMOD model, while the WISER software determined safe distances to aid emergency responses to chemical releases exceeding standard limits. Results: Benzene measurements at the selected stations indicated average emissions of 3.07 µg/ in spring, 3.50 µg/ in summer, 2.95 µg/ in autumn, and 2.35 µg/ in winter. Notably, levels surpassed standards at three locations, posing environmental and health risks to residents’ station 53 and the Takhti sampling area exhibited the highest and lowest benzene emissions, respectively, at 4.24 µg/ and 1.62 µg/ . The dispersion model revealed a maximum annual benzene concentration of approximately 7.89 µg/ , exceeding the standard limit. Safe distances determined by the WISER model ranged from 0.5 to 0.7 µg/ , extending between 50 and 300 meters from the sampling area. Conclusion: The study concludes that benzene emissions are higher in summer and lower in winter at the sampled locations. Distance from emission sources correlates with reduced benzene concentrations, thus minimizing population exposure. Safe areas were identified based on these findings. Given the health risks posed benzene emissions from gas stations, particularly in locations exceeding standard levels, targeted monitoring and control programs are imperative municipal areas and fuel stations.
Golamreza Mousavi; Ahmad Allah-Abadi; Yahya Jalili Darbandi
Abstract
Background & Objectives: With the increasing trend of imports and exports in the country, the number of transport vehicles is also growing at the customs gates across the world. This causes the wastewater disinfection gates to increase in number at the borders of a country. Du to a cationic detergent ...
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Background & Objectives: With the increasing trend of imports and exports in the country, the number of transport vehicles is also growing at the customs gates across the world. This causes the wastewater disinfection gates to increase in number at the borders of a country. Du to a cationic detergent called Benzalkonium chloride, the wastewater produced in these places is not biologically treatable. Therefore, advanced oxidation methods are considered as a viable option for treating the wastewater. In aspect-oriented programming (AOP), catalytic ozonation with activated carbon is regarded as an efficient method of disinfection. The present study aimed to determine the optimal conditions of using activated carbon produced from agricultural waste and activated with NH4CL as a heterogeneous catalyst with Ozone. Methods: In this study, the chemical quality of wastewater was evaluated at the disinfection customs gate of Lotf Abad Using single and catalytic ozonation by NH4Cl-induced activated carbon obtained from agricultural waste as the base material, COD removal was performed in a 200cc continuous reactor. The studied variables were pH, catalyst concentration and the reaction time. In the catalytic ozonation, single absorption and the synergistic effect of the catalysts were also investigated. Results: According to the results of the present study, with the ozone dose of 1 mg/min of alkaline pH in 30 minutes, single ozonation was able to remove only 39.7% of COD while catalytic ozonation with 0.1 g/L of carbon catalyst concentration in the same condition removed 66.8% of COD creating a 13.6% of synergistic effect as well. Conclusion: Activated carbon with NH4CL could noticeably increase the oxidation with ozone. Thus, it could be used as a catalyst in the ozonation reactor in order to remove COD from wastewater. Paper Type: Research Article
Amir Shojaei; Hossein Ghafourian; Linda Yadegarian; Kamran Lari; Mohammadtaghi Sadatipour
Abstract
Abstract Background and Aim :The release of volatile organic compounds from stationary and mobile sources increases the concentration of these compounds in the environment. These compounds are potentially hazardous to the environment and human health. The selection of management and engineering systems ...
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Abstract Background and Aim :The release of volatile organic compounds from stationary and mobile sources increases the concentration of these compounds in the environment. These compounds are potentially hazardous to the environment and human health. The selection of management and engineering systems has become essential for controlling the release of these pollutants. The aim of this study was to use an advanced catalytic ozonation process to reduce the concentration of these pollutants in industrial emissions. Materials and Methods:In this experimental study, the ozonation process in the presence of a catalyst bed containing ZnO nanocomposites coated on zeolite was used to treat the air contaminated with BTEX compounds as indicators of volatile organic compounds on a laboratory scale. In this study, the synthesis of nanocomposites was done using the chemical co-deposition method. SEM, XRD, BET, and FT-IR analyses were performed to investigate the structural properties of the nanocomposites. The initial concentrations of BTEX (50-200 ppm), the flow of the polluted air (5-20 l/h), humidity (0-75%), and ozone dose (0.25-1 g/h) were studied. The concentration of the BTEX compounds was measured by a Gas Chromatography (GC) device according to the NIOSH Guideline 1501. Results:The results of SEM, XRD, BET, and FT-IR indicated the proper synthesis of nanocomposites. Based on the laboratory results, the optimal process conditions were the initial concentration of pollutants equal to 50 ppm, the inlet flow rate of polluted air equal to 5 l/h, relative humidity of 25-35%, and the inlet concentration of ozone equal to 1 g/h. Under these conditions, the removal efficiencies of benzene, toluene, ethylbenzene, and xylene were 98, 96, 92, and 91%, respectively. Simple ozonation and adsorption processes had lower efficiencies than catalytic ozonation and the synergistic effect of the process was evident. Conclusion:Based on the obtained results, the process has the ability to reduce the concentration of BTEX compounds to the specified standards. This process can be used to treat polluted air in BTEX emitting industries that threaten human health and the environment. Article type:Research article Keywords: Volatile Organic Compounds; BTEX; Nanocomposite; Zinc Oxide; Ozone; Polluted Air
B. Heidari; M.H Mehdi Nejad; A.A. Najafpour; A. Zafarzadeh; H. Elahi
Abstract
Background & Objective: The issues of environmental engineering , due to its technical , environmental, social and economic factors are complicated. So, it is difficult to determine which variables are more effective. The purpose of this study was to investigate the effective variables by using ...
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Background & Objective: The issues of environmental engineering , due to its technical , environmental, social and economic factors are complicated. So, it is difficult to determine which variables are more effective. The purpose of this study was to investigate the effective variables by using AHP and choose the best method of wastewater treatment (Soleimani Village). Materials & Methods: This is a descriptive study with applying approach. By using AHP is the preferred choices were determined. This method was evaluated by using software Expert Choice. In this regard, after considering the factors affecting or affected by, 3 criteria and 15 sub-criteria, and then the analytic hierarchy process were used. Then, the wastewater treatment processes were prioritized. The processes are constructed wetland systems, rotating biological discs, extended aeration with floating Media and activated sludge. They were based on technical criteria, economic, efficient of treatment process, sub- criteria, weighting and prioritization. Results:The results showed that weight scores of constructed wetland, rotary biological disc, extended aeration with floating Media and activated sludge were 0.36, 0.28, 0.2 and 0.15, respectively. Therefore, the treatment of choice in rural areas was constructed wetland treatment. Conclusions: The results show economic criteria are more effective to make the final decision. By the way, the technical criteria were also considered (e.g., ease of operation and construction, etc.) It can be concluded that the wetland method is the best alternative for Soleimani village.
elham shahri; nematolah khorasani; gholamreza noori; ferdos kord mostafa pour; mohammad velayatzadeh
Abstract
Background & Objective: The heavy metals are considered as the pollutants which create too much problems in aquatic ecosystems for aquatics, and consequently, humans. This study aims to demystify risk assessment of some heavy metals concentrations such as Nickle, Cadmium, Lead and Zinc in the muscles ...
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Background & Objective: The heavy metals are considered as the pollutants which create too much problems in aquatic ecosystems for aquatics, and consequently, humans. This study aims to demystify risk assessment of some heavy metals concentrations such as Nickle, Cadmium, Lead and Zinc in the muscles of Otolithes ruber, Parastromateus niger, Scomberomorus commerson and Sphyraena jello fishes in 2013. Material & Methods: 96 samples from the aforementioned fishes were taken from both coastal and marine areas of Chabahar port (Oman sea). Wet Digestion method is applied to extract the considered metals from the tissues, and the concentrations of the heavy metals were measured by Atomic Absorption Spectrophotometer Younglin AAS8020. All statistical analyses were performed by SPSS (V. 17) using ANOVA along with Duncan test. Results: The results showed the highest and lowest concentrations of Cd were in Sphyraena jello and Otolithes ruber, respectively. The lowest Concentration of Pb was in Sphyraena jello. The highest and lowest concentrations of Ni and Zn were observed in Sphyraena jello and Scomberomorus commerson, correspondingly. The highest concentration of adsorbed Cd, Ni and Zn metals were measured in Sphyraena jello in the coastal area samples in children. Conclusion: Concentrations of Cd, Pb and Zn were lower than the determined proportions of FAO, WHO, UKMAFF, NHMRC and FDA. Ni concentration was higher than theGlobal Standards in Sphyraena jello.
Mina Taghizadeh; Azade Kazemi
Abstract
Background and purpose: Using plants to monitor contamination is a suitable method. In this regard, biomonitoring is one of the inexpensive and easy ways to evaluate the quality of air and soil. Considering the problem of contamination of metals such as chromium, cadmium, nickel and lead in the industrial ...
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Background and purpose: Using plants to monitor contamination is a suitable method. In this regard, biomonitoring is one of the inexpensive and easy ways to evaluate the quality of air and soil. Considering the problem of contamination of metals such as chromium, cadmium, nickel and lead in the industrial city of Arak, which is reported by researchers, it is likely that these pollutants will be highly absorbed by existing greenhouse plants. Therefore in this study, the amount of heavy metals contamination in mulberry trees (Morus alba) was investigated in different site of the Arak city during the months of May to June 2012. Materials and methods: The amount of 13 elements was measured in the fruit and leaf organs of the Morus alba var. pendula and Morus alba with three replications in the landscapes of the Arak city. The map of distribution of heavy metals concentration in fruit and leaf separately in each individual case was carried out using Inverse Distance Weighted method in GIS environment. Results: Based on the comparison of the limitations of metals in food products and the amount of metals found in fruits of berry trees in Arak areas, the berries were high and unauthorized due to contamination of aluminum (29 mg l-1), cadmium (0.66 mg l-1) and lead (1.3 mg l-1). Metal pollution contamination mapping showed that the distribution of most metal contaminants is outside the industrial zone and there is more accumulation in the central regions. Probably, the dispersion of heavy metal particles from industrial sites has led to an increase in the concentration of metals in these areas. Conclusion: Therefore, due to the contamination of the mulberry fruit of these heavy metals, there is a serious warning about the consumption of this fruit, especially in the city of Arak.
Mohsen Niazi; Ali Naghizadeh; Mansour Baziar
Abstract
AbstractBackground and purposeThe turbidity of treated water is measured as an important parameter in determining the quality of drinking or industrial water in all treatment plants. Due to the importance of the prevalence of pathogens such as Giardia and Cryptosporidium, which cause dangerous diseases ...
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AbstractBackground and purposeThe turbidity of treated water is measured as an important parameter in determining the quality of drinking or industrial water in all treatment plants. Due to the importance of the prevalence of pathogens such as Giardia and Cryptosporidium, which cause dangerous diseases such as dysentery, the relationship between reducing turbidity and increasing the elimination of these microorganisms has been proven in studies.Materials and methodsIn this study, an artificial neural network (ANN) model and multiple linear regression(MLR) were developed and their performance was compared to predict the turbidity of treated water of Tabas water treatment plant. Total dissolved solids, pH, temperature and input turbidity of raw water were used as input parameters of the models in the predictions. The best backpropagation algorithm and number of neurons were determined to optimize the model architecture.ResultsThe results showed that the Levenberg–Marquardt algorithm was selected as the best algorithm and the number of optimal neurons was determined to be 16.Also, the results of the sensitivity analysis of the neural network model showed that the input turbidity with a value of 29% is the most important parameter in the development of the ANN model.ConclusionThe results of correlation coefficient of MLR and ANN models were obtained for training data 0.63 and 0.8921 and for testing data 0.60 and 0.8571, respectively, which show the superiority of ANN model in Predicting the turbidity of the output of Tabas water treatment plant.
Mahdi Asadi Ghalhari; Amin Kishipour; Roqiyeh Mostafaloo; Yalda Arast
Abstract
Background and Purpose: Today, the production of plastic materials has multiplied with the growth of population and the development of industry in the world. Micro-plastics are released into the environment by the decomposition of plastic materials. The World Health Organization (WHO) has called these ...
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Background and Purpose: Today, the production of plastic materials has multiplied with the growth of population and the development of industry in the world. Micro-plastics are released into the environment by the decomposition of plastic materials. The World Health Organization (WHO) has called these particles emerging pollutants due to their highly durable and bioaccumulative. The present study reviews the characteristics, health hazards, values, as well as the efficiency of different methods of eliminating micro-plastics in aquatic environments. Materials and Methods: In this review study, the keywords Micro-plastic, Water-drinking, Pollution, and Removal were searched and studied in articles from 2000 to 2020 published by Pubmed, Google scholar, Science direct, and Scopus. Results: Studies show that in addition to the food chain, this pollutant is also present in bottled drinking water, which can affect human health, the environment and living organisms in aquatic environments. conclusion: It is suggested that more studies be done on this pollutant in aquatic environments, especially in Iran. In addition, educate people about less use of plastic in everyday life, teach them how to recycle properly, and get help from the industry to provide a suitable alternative to plastic. Article type: A review article.
Zahra Yaghoubzadeh; Resa Safari
Abstract
Abstract
Background and objective: Biological assessment of water resources is of particular importance and the presence of pathogens in these resources affects the health of consumers. The aim of this study was to determine the bacterial contamination of water including total coliforms, fecal ...
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Abstract
Background and objective: Biological assessment of water resources is of particular importance and the presence of pathogens in these resources affects the health of consumers. The aim of this study was to determine the bacterial contamination of water including total coliforms, fecal coliforms and fecal streptococci in the Azad dam lake.
Methods and Materials: In this study, Sanandaj Azad dam water was evaluated for the indicator bacteria during one year (from May 2015 to June 2016). Sampling was performed from five stations in the areas of lake, transients and river. Statistical analysis of the obtained data was accomplished by ANOVA and Duncan tests using SPSS 18 software (P<0.05).
Results: Monthly analyzes showed that the maximum and minimum mean of total bacteria were recorded in the months of January (6.7×105 CFU / 100ml) and September, (1.6×104 CFU100ml). The maximum total mean value of total coliform was 2.3 × 104 CFU / 100ml in December and the minimum one was 62 CFU100ml in July. Neither thermophilic coliforms nor fecal streptococcus were observed in the lake of the dam in taken samples.
Conclusion: Based on the obtained results, the collected water behind the dam can be used without any purification for agricultural purposes and fish farming. However, this water supply is not suitable for drinking due to the observed microbial load.
Mohammad Saleh Ali Taleshi; Hamid Reza Azimzadeh; Mohammad Taghi Ghaneian; Seyedeh Mahdieh Namayandeh
Abstract
Background and objective: Every week, hemodialysis patients need to approximately 400 l of water for producing dialysis fluids. So, the quality of water used for treatment of hemodialysis patients is an important factor. This study evaluated the performance of reverse osmosis systems of Yazd educational ...
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Background and objective: Every week, hemodialysis patients need to approximately 400 l of water for producing dialysis fluids. So, the quality of water used for treatment of hemodialysis patients is an important factor. This study evaluated the performance of reverse osmosis systems of Yazd educational hospitalsdialysis centers for improving the quality of water used. Materials and Method: In this study, 48 samples of input and output of reverse osmosis systems collected in two educational hospitals during October to December in 2013. Then samples analyzed from the aspect of the physicochemical parameters such as calcium, magnesium, sodium, potassium, total dissolved solids (TDS), sulfate, chloride, total hardness (TH), EC and pH using standard methods of experiment and the results were analyzed using SPSS v.16. software. Results: The findings of research showed that there is significant difference with 99% confidence between input water to reverse osmosis from aspect of calcium, TDS, EC, pH. Results of paired T-Test and evaluation of performance of reverse osmosis showed that there is significant difference between water quality, before and after of system in the hospital No.1. Except chloride and sodium, there is a significant difference between water qualities in two phases in the hospital No.2. Conclusion: The results of this research showed that reverse osmosis system improves the quality of water used for hemodialysis significantly, but in continuous operation may be faced with reduced efficiency. Thus, using combination methods of water treatment is necessary to prevent the physicochemical pollution for ensuring the hemodialysis with good quality. Paper Type: Research Article
Masoumeh Moghaddam Arjmand; Maziar Naderi; Solmaz Gholami
Abstract
Abstract
Background and aims: Drinking water pollution is a serious threat for public water supply. Water disinfection has a very important role in the reduction of pathogenic microorganism. Water electrodisinfection is an efficient and cost-effective method in water disinfection. The aim of ...
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Abstract
Background and aims: Drinking water pollution is a serious threat for public water supply. Water disinfection has a very important role in the reduction of pathogenic microorganism. Water electrodisinfection is an efficient and cost-effective method in water disinfection. The aim of this study was the survey of inactivation in two types bacteria (as index and resistant) by electrochemical process in the presence of supporting electrolytes.
Materials and methods:Inactivation of E.Coli and Bacillus subtilis spore was studied at current intensity of 500mA, with each of the supporting electrolytes including CuI, NaBr and KCl. The type of electrodes was steel and the distance between electrodes was 2cm. Furthermore, the tests carried out in monopolar mode Fe-Fe, neutral pH and experimental temperature (21o c). The number of bacteria, amount of supporting electrolyte, voltage, and electrochemical action time were investigated.
Results:Adding the supporting electrolytes to the electrochemical disinfection process decreased bacterial resistance. Copper iodide (CuI) on 2 mg/l concentration showed more efficiency in bacterial inactivation.
Conclusion:Supporting electrolyte CuI with concentration of 2 mg/l both enhances the electrochemical process performance due to an increase in ionic transmission rate and voltage current. Also, this decreases electrochemical inactivation time and increases bactericidal effect.
Mostafa Abyareh; Farhad Nejadkoorki; Mohammad Reza Ekhtesasi; Mohammad Akhavan Ghalibaf
Abstract
Abstract Backound and purpose: The communities have been faced the environmental challenges by dust particles as an important part of air pollution that are emitted into the atmosphere every day by chimney of factories and power plants out. The aim of this study was to determine the quality and quantity ...
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Abstract Backound and purpose: The communities have been faced the environmental challenges by dust particles as an important part of air pollution that are emitted into the atmosphere every day by chimney of factories and power plants out. The aim of this study was to determine the quality and quantity of industrial dust around the Yazd Steel Company to control and supervise the industrial dust to make the better environmental condition. Materials and Methods: In this study, according to the wind direction, the falling dust particles, were collected and weighted in two sediment stations before and after the company from 1/2/2016 to 30/4/2016. The sampling was done by MDCO. Then, the taken samples transferred to an elemental analysis laboratory, and the amounts of dust-forming elements were measured by XRF device. Results. Based on the obtained results, the maximum and minimum levels of the concentrations of falling dust particles were 32.9g/m2 on March for,0.0014 g/m2 on February for SiO2 and SrO respectively. the major elements and chemical compounds of dust included: SiO2، CaO، CO2، Al2O3، MgO، Fe2O3، K2O، Na2O، SO3، TiO2، Cl، p < sub>2O5، MnO، ZnO، Pt، Au، SrO. . Conclusions: The results of statistical tests demonstrated that there was a significant difference between the amounts of these elements before and after the company. Therefore, proper management and more accurate monitoring are necessary to protect the environment in this industry