Iranian Journal of

Background and Objective: Olive Mill Wastewater (OMWW) is one of the most polluted sanitary wastewaters that its ineffective treatment will cause severe pollution of the environment. In this study, OMWW treatment wasinvestigated using combined electrocoagulation and novel advanced oxidation process.
Materials and Methods: Biodegradability, efficiency and kinetics of removal of turbidity and organic matter from the OMWW by applying the operational parameters of electrocoagulation such as current density (0-0.77 A/dm²), type of anode electrode, reaction time (0-45 min) were investigated. Various types of advanced oxidation processes were performed to determine the the efficiency of removal of TOC and kinetics and biobegradability.
Results: The optimum condition for removing turbidity, BOD, TOC and consumed Iron anode electrod in electrocoagulation were 78%, 57%, 72% and 583 mg/ per liter of wastewater, respectively. Thus, the kinetic of TOC removal was first-order and was 0.027 min^-1. The TOC removal efficiency of pretreated OMWW in oxidation processes of US, H₂O₂, SOP, O₃ / H₂O₂, COP, COP/US and H₂O₂/COP/US were measured as 8%, 15%, 20%, 25%, 61%, 68% and 75%, respectively. The highest biodegradability index (BOD/TOC) in the COP/US/H₂O₂ process was increased 1.5 times.
Conclusion: The advenced oxidation process of COP/US/H₂O₂ follwed by electrocagulation demonstrated an effective treatment of OMWW and improved its biodegradability. Therefore, this process can be used for efficient treatment of OMWW in olive and similar industries.
 

Background and Objective: This research tries to analyze the spatial distribution and trend of arsenic level changes in the underground water resources of the Sirjan basin, and also to evaluate and analyze the factors affecting the concentration of this element in these water resources.
Materials and Methods: Sampling of underground water sources in the study area was done by systematic-random method and arsenic concentration was done by ICP-MS method in the laboratory. Also, to evaluate the factors affecting the concentration of arsenic in the underground water resources of Sirjan bathe sin, the method of land systems analysis was used.
Results: The results of the research show that the amount of arsenic in all samples is higher than the Guidelines provided by the World Health Organization so the amount of this element in the underground water sources of the study area varies between 30 and 390 µg/L. Samples No. 9, 13, and 16, which are located in the deepest parts of the basin, have the highest amount of arsenic. For this reason, the durability of water in this part of the basin increases. This reduces the intensity of the current. As a result, according to the cumulative effect law, this process can lead to an increase in arsenic concentration.        
Conclusion: The evaluation of changes in the concentration of arsenic in the underground water resources of the study area indicates that the concentration of this element had a high increasing trend. According to the results, the location of the studied area in the center of hydrothermal and geothermal processes (copper mineralization belt in Iran), the cumulative effect, and the effect of pH on the absorption and desorption of arsenic are among the most important factors affecting the increase of arsenic in the underground water resources of Sirjan Basin.