Toktam Shahriari; Abdolreza Karbasi; Milad Reihani
Abstract
Introduction: Oil refinery is one of the industrial centers and its wastewater has a lot of environmental pollutants which are a serious threat to the environment and water resources. In this study, an electrocoagulation reactor was used to remove and reduce the amount of Chemical Oxygen Demand (COD) ...
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Introduction: Oil refinery is one of the industrial centers and its wastewater has a lot of environmental pollutants which are a serious threat to the environment and water resources. In this study, an electrocoagulation reactor was used to remove and reduce the amount of Chemical Oxygen Demand (COD) in the wastewater from the API unit of the Shazand Oil Refinery in Arak, which is a gravity separator of water and oil. Material and methods: In order to simulate the electrocoagulation process in experimental conditions, a 15 × 14 × 13 cm Plexiglas pilot was designed, in which six 10 × 12 cm aluminum electrodes with a thickness of 2 mm were put as sacrificial electrodes during the process. The distance between the electrodes was 2 cm. The monopolar arrangement was selected for electrodes. At each stage of the experiment, after measuring the pH and COD of the initial wastewater, the volume of 2 L was poured out as an internal sample into the coagulation reactor; after the electrochemical process, the secondary pH and COD were measured to determine the effect of the electrocoagulation process. Results and discussion: In this research, the effect of time, pH, and voltage in the electro-flocculation process has been evaluated. The amount of COD, pH, and lead were measured 450 mg/L, 5.5 and 5.27 mg/L in initial wastewater, respectively. To avoid the overlapping effect of time, pH, and voltage during the process, the value of one of the parameters was changed and two other parameters were kept constant and the optimum value was determined. In order to minimize the errors during the testing process, each step has been repeated three times. After performing different stages of the test and collecting and analyzing the results, the optimum time of the test, optimum pH, and optimum voltage were considered as 90 min, 6 and 30 V, respectively. Consequently, the COD decreased from 450 to 193 mg/L and 99.05% of lead was removed. The results of the experiments showed that by increasing the duration of electrolysis, the removal rate also increases. The results of other research also showed that the flow density is directly related to the reaction time, and by increasing the time, more removal rate can be obtained. As the results demonstrate, the removal rate is directly related to the applied voltage, which is due to the more production of aluminum hydroxides in the wastewater, which plays the role of coagulant. In previous studies, the results also indicated an increase in the removal rate of pollutants by increasing the applied voltage. The pH also had an important effect on the results. At low pH values, cationic monomeric species such as Al3+ and Al(OH)2+ were obtained from the dissolution of the aluminum anode. On the other hand, with the excessive increase in the pH of the solution, such compounds as Al(OH)4- were formed, which caused disruption and sluggishness in the removal process. Conclusion: The results of this study showed that aluminum hydroxides as coagulants, which are produced by the electrochemical dissolution of the sacrificial electrodes, play a major role in the pollutant removal process. The higher their production rates, the more removal will occur. To do this, the optimal parameters for producing them should be optimally set. By increasing the electrolysis time, the amount of aluminum hydroxides also increases. Also, adjusting the pH of the solution at an appropriate range provides optimum conditions for the production and formation of gelatin aluminum hydroxide polymer.
Fariba Zamani Hargalani; Abdolreza Karbassi; Seyed Masoud Monavari; Parviz Abroomand Azar
Volume 11, Issue 2 , July 2013
Abstract
Anzali, one of the most important international wetlands, is located on the southern coast of the Caspian Sea in Iran. This wetland receives discharges of domestic, agricultural and industrial wastewater, which affect the distribution of elements. In this study, ten sediment samples from the Anzali wetland ...
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Anzali, one of the most important international wetlands, is located on the southern coast of the Caspian Sea in Iran. This wetland receives discharges of domestic, agricultural and industrial wastewater, which affect the distribution of elements. In this study, ten sediment samples from the Anzali wetland were collected and analyzed for total concentration of metals (As, Cd, Cr, Cu, Ni, Pb, Zn and Fe). The results showed relatively higher concentrations of most elements in comparison to that of crust. The chemical partitioning of metals in each sample was determined in four fractions (Loosely bonded, Sulphide bonded, Organo-metallic bonded, Resistant bonded). Based on the chemical partitioning of metals, As and Cd were the most abundant in the loosely bonded, so these elements were major hazard for the aquatic environment and were a major pollutant in this area. Cd is the metal that showed the highest percentages in the Organo-metallic bonded. As, Fe and Cr are displayed in the greatest percentages in the resistant bonded; this imply that these metals are strongly linked to the sediments.
Taraneh Sharmad; Mohammad Hossein Adabi,; Abdolreza Karbassi; Hossein Bageri
Volume 9, Issue 3 , April 2012
Abstract
In the present study depositional temperature, diagenetic type and major climatic changes are investigated using oxygen and carbon stable isotopes. For this purpose, a sediment core (140 cm long) of 12 Km distance from the coast (near Langroud city), was collected from the southern Caspian Sea.A sedimentation ...
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In the present study depositional temperature, diagenetic type and major climatic changes are investigated using oxygen and carbon stable isotopes. For this purpose, a sediment core (140 cm long) of 12 Km distance from the coast (near Langroud city), was collected from the southern Caspian Sea.A sedimentation rate of 0.9 cm/year was obtained based on a 210Pb and 137Cs isotope study of the sediment core. The depositional temperature and diagenetic type were obtained based on Mass Spectrometry analysis of sediment samples. The oxygen-carbon isotope study indicates a very low depth of burial diagenesis. Water temperature based on the heaviest oxygen isotope value with least alteration, shows around 21ºCduring sedimentation, (120 years ago) while CTD results during sampling show the same result, so it seems that there have been no major climatic changes in the study area.
Ebrahim Fataei,; Seied Masoud Monavari; Amir Hesam Hasani; Seied Ahmad Mirbagheri; Abdoreza Karbasi
Volume 8, Issue 2 , January 2011
Abstract
For assessment of water quality in Gharasou River, located in the Northwest of Iran, multivariate statistical analysis was used. During the period of one year, 18 physical, chemical and microbiological parameters were sampled in 11 sampling stations. The measured data were analyzed by a multivariate ...
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For assessment of water quality in Gharasou River, located in the Northwest of Iran, multivariate statistical analysis was used. During the period of one year, 18 physical, chemical and microbiological parameters were sampled in 11 sampling stations. The measured data were analyzed by a multivariate statistical approach, Cluster Analysis (CA). Based on CA analysis the stations were divided to three groups of highly polluted (HP), moderately polluted (MP), and less polluted (LP) stations. The results of the study revealed that multivariate statistical techniques are an effective statistical method for water quality assessment, identification of pollution sources/factors in water quality for effective water quality management. As Extracted clustered information can be used in reducing the number of sampling sites on the River without missing much information.
