Saeed Akbari; Mohammad Hadi Dehghani; Mehdi Salari
Abstract
Background and objective: Due to its high concentration on the surface and its pathogenic function, fluoride is noticeable. Fluoride at high concentrations can be dangerous. The World Health Organization's allowable concentration is 1.5milligrams per liter. The aim of this study was to take chitosan ...
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Background and objective: Due to its high concentration on the surface and its pathogenic function, fluoride is noticeable. Fluoride at high concentrations can be dangerous. The World Health Organization's allowable concentration is 1.5milligrams per liter. The aim of this study was to take chitosan from shrimp shells and evaluate its performance in the removal of fluoride in aqueous solutions. The purpose of this study was to isolate chitosan from shrimp shells native Persian Gulf and evaluate its performance in the removal of fluoride in aqueous solutions. Materials & Methods: Chitosan from shells native Persian Gulf shrimps in three stages, protein , minerals and de-acetylation separation. The isotherms and adsorption kinetics were evaluated in optimal conditions. Results: The results showed with 100 ml of 4 Results: milligrams per liter of fluoride, the fluoride removal at pH = 7, 60 minutes contact time and adsorbent concentration of 2 grams per liter respectively. The result of the absorption curve obeys a second-order. Freundlich adsorption isotherm data were more consistent. Maximum capacities of 0.157 milligrams per gram was with the removal of fluoride with chitosan. Conclusion:The extracted chitosan can be an effective adsorbent for the removal of fluoride from contaminated water so that the amount of fluoride in drinking water is reduced to below the allowable level of fluoride.
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.
Mahdi Sadeghi; Kaveh Khosravi; Seyed Mostafa Khezri; Abotaleb Bay
Abstract
Background and objective: Today, with the development, the need for water in the production processes is increasing and so we have sewage with high level of pollution. This study aimed at determining the effectiveness of electrocoagulation for treatment of dairy industry wastewater in a continuous flow ...
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Background and objective: Today, with the development, the need for water in the production processes is increasing and so we have sewage with high level of pollution. This study aimed at determining the effectiveness of electrocoagulation for treatment of dairy industry wastewater in a continuous flow (case study wastewater of Sabah cheese factory Gonbad-e Qabus). Materials & Methods: This study was descriptive and analytical with experimental approach. The samples were collected from Sabah dairy factory and put into the electrocoagulation reactor with continuous flow. At retention times of 20, 40 and 60 minutes with an electric current of voltages 20, 40 and 60 were purged. The samples were carried to the laboratory and various tests of COD, BOD, pH, turbidity, nitrate and phosphate were done. Then the results were compared and analyzed. Results: The mean of COD, BOD, nitrates, phosphorus and turbidity was 4933 ± 231, 600 ± 50, 48.6 ± 14.8, 28 ± 0.7 mg/L and1329 ± 297.6 NTU respectively. The most removal efficiency of these parameters during the study was 84.62, 66.67,55, 54.2 and 85.1 percent respectively. Conclusion:This study showed that electrocoagulation process as a pre-treatment process can remove organic matters, turbidity and nutrients. It can also reduce organic load and increase wastewater biodegradability and it can be an effective option for treating wastewater effectively and thereby preventing pollution in our environment and water resources.
Majid Kermani; Mohsen Dowlati; Ahmad jonidi jaffari; Roshanak Rezaei kalantari
Abstract
Background and objective: Air pollution is one of the major factors threatening human health and our environment. This study aimed at the comparative investigation of Air Quality Health Index (AQHI) and its application in the city of Tehran since 2007 to 2014. Materials & Methods: This Study ...
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Background and objective: Air pollution is one of the major factors threatening human health and our environment. This study aimed at the comparative investigation of Air Quality Health Index (AQHI) and its application in the city of Tehran since 2007 to 2014. Materials & Methods: This Study was a descriptive–analytic one. First, the required data were taken from Department of Environment and the Air Quality Control Company. The data were validated by the World Health Organization criteria .The air quality health index was measured based on the air quality standard tables and classified into low, medium, high and very high degrees. Results: The results show that according to air quality health index, the level of air pollution in Tehran has been undesirable since 2007 to 2014 and in 95%,92%,73%,65%,57%,65%,52%,46% of days Air quality has exceeded the standard level respectively .So, the level of risk has been high and sometimes very high. Conclusion:As a result, due to high level of air pollution and its dangerous effects, proper planning and management should be considered in environmental health sectors to control and reduce air pollution.
Alireza Ehsanzadeh; Farhad Nejadkoorki; Ali Taleb
Abstract
Background and objective: Air pollution in Tehran, because of high concentration of pollutants, has caused various diseases and many problems concerning the public health and welfare of citizens and also damages to the environment and living organisms. Materials & Methods: Air Quality Index ...
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Background and objective: Air pollution in Tehran, because of high concentration of pollutants, has caused various diseases and many problems concerning the public health and welfare of citizens and also damages to the environment and living organisms. Materials & Methods: Air Quality Index (AQI) is a key tool to monitor the air quality, to realize the effects of air pollution on health and to choose methods against air pollution. This study aimed at modeling and estimation AQI by CART algorithm and adaptive boosting algorithm (AdaBoost). Hourly data on concentration of air pollutants and meteorological parameters related to Gholhak stations in Tehran was used for modeling and estimation of AQI. Results: The results showed that CART model had better performance than AdaBoost model. To evaluate these models, root mean square error (RMSE), mean absolute error (MAE), mean squared error (MSE) and correlation coefficient (R) of the CART model for the test, were respectively, 0.75, 0.101, 0.563, and 0.99 when compared to the AdaBoost model (RMSE=7.1, MAE=5.11, MSE=50.52 and R=0.95) which implies the absolute superiority of the CART model than the AdaBoost model. Conclusion:The results of this study showed that regression decision tree model can be used as an efficient model for modelling and estimation of urban air quality index.
Elahe Rezaie; Mahdi Sadeghi; Ghodratollah Shams Khoramabadi
Abstract
Background and objective: One of the major environmental problems of municipal landfill is leachate. Electrochemical methods are considered for the treatment of leachate. This study aimed at the treatment of landfill leachate electrochemical method using a platinum electrode and graphite based on a laboratory ...
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Background and objective: One of the major environmental problems of municipal landfill is leachate. Electrochemical methods are considered for the treatment of leachate. This study aimed at the treatment of landfill leachate electrochemical method using a platinum electrode and graphite based on a laboratory scale. Materials & Methods: In this study, the equipment for electrochemical reactor included an anode electrode made of platinum and a cathode electrode made of graphite. Chromium and organic matter removal percentage in the electric current density range of 1, 2, 3, 4 A and reaction time of 1, 2, 3, 4, 5, 6, 7, and 8 hours were surveyed. Results: The results showed that electrical coagulation process can increase removal of organic matter and heavy metals and by increasing the time the removal of COD and BOD and chromium will increase. Meanwhile, the rate of degradation wills elevates. By increasing the intensity of electric current, the time required to achieve the same removal efficiency is reduced and by reducing the amount of electrical current, the required time increases. Conclusion:The results indicated that electrochemical process, by using a platinum electrode and graphite is a method for treating wastewater containing heavy metals, BOD and COD .Elerochemical process as a pre-treatment process can remove organic matters, heavy metals. It also reduces the organic load and increases the degradation of sewage. The method can be used as an effective option for the treatment of sewage, prevention of environmental pollution, and protection of water supplies.
Vahid Jabari; Alireza Safari; Alireza Ranaei
Abstract
Background and objective: In 1393, the daily average of waste produced in Qazvin was 300 tons that Per capita waste generation is 680 grams per person per day. To control these wastes, methods including composting, landfill and waste-to-energy conversion should be applied. The most common method of converting ...
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Background and objective: In 1393, the daily average of waste produced in Qazvin was 300 tons that Per capita waste generation is 680 grams per person per day. To control these wastes, methods including composting, landfill and waste-to-energy conversion should be applied. The most common method of converting waste to energy incineration is done in the power plant. According to the World Bank, to build a waste incineration plant for burning waste without using additional fuel. The calorific value must be at least 7 Mj/kg and not less than 6 Mj/kg .Also the weekly fluctuations should be less than 20%. Materials & Methods: In this study the samples of mixed wastes were taken to determine the quantitative and qualitative characteristics of the mixed wastes for one year. The samples were collected during one year. (Saturday, Monday and Thursday of each week) each time 5 samples were taken. To determine the characteristics of the output waste from processing facilities. Analysis of moisture, combustible materials and ash content, heating value were done according to standard criteria. Results: The results showed that the calorific value of Urban mixed waste of Qazvin is 6.133 Mj / Kg. The percentage of moisture was 50.3%, the ash 30.1% and the combustible materials 27. 9% .The calorific value wastes output of processing facilities was 11.8 Mj / Kg. Conclusion:The waste output of processing facilities is more adaptable with Tanner pattern. Due to the high calorific value wastes output from processing facilities and its low moisture content. The Refuse derived fuel facility should be applied for waste management in Qazvin.
Hosein Alidadi; Habibollah Esmaili; Sayede Fateme Aghaee; Sayed Abolfazl Mirzaee; Mohammad Naser Shafiee Jafarabadi
Abstract
Background and objective: Nowadays, wastes of dental offices have become a major environmental issue for their hazardous, toxic and pathogenic features. The aim of this study was to survey on the wastes produced in dental offices of Bojnord. Materials & Methods: In this study 28 dentists' ...
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Background and objective: Nowadays, wastes of dental offices have become a major environmental issue for their hazardous, toxic and pathogenic features. The aim of this study was to survey on the wastes produced in dental offices of Bojnord. Materials & Methods: In this study 28 dentists' offices were studied. From each office, three samples were taken for three consecutive day’s week in a week. The samples were manually separated into 64 different components and weighed with a digital scale .The components were classified in 4 groups based on their hazardous characteristics. We analyzed the data by using descriptive statistics, SPSS 19 and the Excel software. Results: The total wastes production was 6162.31 Kg in one year. The share of infectious, semi household, chemical - pharmaceutical and toxic wastes was 40.85, 49.99, 7.47, and 1.69% respectively. The main wastes produced in dental offices consisted of 16 components which can be considered as more than 80% of the dental wastes. Conclusion:It is suggested that dentists should be trained to reduce, separate and recycle the wastes in accordance with relevant rules and regulations. Because the segregation of recyclable parts from dental wastes can lead to reduction of a large amount of wastes and so that the costs of collection, transportation, disposal and disinfecting will be reduced.