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Background and Objectives: Petrochemical wastewater contains some kinds of toxic substances but if the effluent is treated properly, its reuse will be possible. This study aimed to evaluate the efficiency of wastewater treatment of Shazand Petrochemical Corporation and feasibility of its effluent reuse in green space irrigation and cooling towers. Materials and Methods: In this descriptive study, the results of tests conducted by the laboratory of Shazand Petrochemical Corporation in 2016 were evaluated and analyzed, and then the feasibility of its effluent reuse in irrigation of green spaces and cooling towers was investigated. So the amount of chemical oxygen demand (COD), total suspended solid (TSS), Fecal Coliform, Total Coliform, turbidity and free chlorine in effluent of pond chlorination and also the amount of silica, alkalinity, calcium hardness, sulphate, COD, electrical conductivity and iron in the effluent of reverse electrodialysis unit were measured. Results: The results showed the maximum efficiency of wastewater treatment in the removal of COD was 98 percent. The amount of parameters in the effluent of chlorination pond was in accordance with the environmental standards for irrigation of green spaces and treated wastewater in the electrodialysis unit that with having maximum 0.12 mg/L iron, 126 mg/L sulfate ,and electrical conductivity 695 ϻs/cm was suitable for use in cooling towers. Conclusion: The results of this study demonstrate that the effluent of chlorination pond can be used for irrigation of green space and also the treated wastewater in reverse electrodialysis unit can be used in cooling towers. [ABSTRACT FROM AUTHOR]

Background and Objective: Chemical dyes used in the textile wastewater besides having harmful effect on the environment, have carcinogenic and mutagenic effects. Methylene blue has harmful effect on living organisms in short period of exposure. The goal of this study was optimization of the catalytic ozonation process by pumice modified by magnesium nitrate in removal of methylene blue dye based on Taguchi statistical model. Materials and Methods: In this experimental study ozonation process was in a batch ozonation reactor. The prepared pumice was crushed and pulverized by standard ASTM (American Society for Testing and Materials) sieves at range of 70 mesh, then modified by magnesium nitrate. Effective factors such as reaction time, initial dye concentration, adsorbent dose, and initial pH at 4 different levels were considered using an L-16 Taguchi method. Residual concentration of contaminants was read using a spectrophotometer at a wavelength of 663 nm. Analysis of data was performed using one- way variance and calculation of S/N (signal- to- noise) rate. Results: The results showed best conditions for removal dye were at contact time of 15 min, pH of 10, dye concentration of 50 mg/l,and adsorbent dosage of 0.7 g/L and efficiency of dye removal was 98%. Analysis of variance results indicated that the reaction time was the most important variable influencing the dye removal percentage with the contribution value of 51.8% and pH was the least important variable influencing the dye removal with the contribution value of 3.8% Conclusion: The results showed that ozonation process can be a selective method to reduce the concentration of pollutants in textile wastewater effluent. [ABSTRACT FROM AUTHOR]

Background and Objective: The percence of organic compounds resistant to biodegradation has become one of the most important environmental challenges in the chemical and petrochemical industry in this century. Phenol or hydroxyl benzene as an aromatic hydrocarbon discharged into the environment through certian industrial effluents which, thereby, pollutes water resources. This study examined the performance evalution of oxidizing agents of peroxide hydrogen, persulfate and periodate activated by ultrasound for removal of phenol from aqueous solutions. Materials and Methods: In this experimental study, the treatability of polluted effluent using US/S2O8, US/IO4 and US/H2O2 with a frequency of 40 kHz for the treatment of contaminated aqueous phenolic compounds were investigated. The effects of operational parameters such as the concentration amount of persulfate(0.001-0.005 M), peroxide hydrogen (0.004-0.1M),and periodate (0.001-0.005 M),, in different contact times in pH of (3,7 and 10) and the impact of changes in the ionic strength in the contact times were selected as the variables of the study. Results: The results of this study showed that increasing the concentration of oxidation significantly increases the removal efficiency and then a decreasing trend was observed in the removal of phenol. So that, optimal concentration of persulfate, periodate,and hydrogen peroxide were selected as 0.003M 0.004M 0.1 M/l, respectively. Study of different changes of pH showed that all three processes had the most removal efficiency at pH= 3 and ionic strength has reduced the US/S2O8 process efficiency and had no effect on the other processes. Conclusion: The results of this study indicated that combined ultrasonic and persulfate process in the optimal conditions had the highest efficiency compared to the other processes. Therefore, persulfate can be used as a good oxidizer together with ultrasonic waves to remove phenol in aqueous solutions. [ABSTRACT FROM AUTHOR]