Iranian Journal of

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Background and Objectives: Effluent generated in several industries contains phenolic compounds, which have been classified as priority pollutants. Due to its toxicity, the conventional systems are inefficient for treatment of phenol-Laden wastewater. Biological processes using pure microbial culture, including fungi and yeast, are environmentally friendly techniques capable of complete destruction of contaminants.
Materials and Methods: This work was aimed at investigating the efficiency of a fungi specie in the decomposition of high concentrations of phenol ranging from 500 to 20000 mg/L. Several batch reactors were operated at different phenol concentration. The concentration of residual phenol was monitored over time using colorimetric method 4-aminoantipyrine. The removal efficiency was calculated considering the initial phenol concentration.
Results: Experimental data indicated that the phenol could efficiently degrade using the selected culture. The developed granules could completely degrade phenol at concentrations up to 20000 mg/L.
Conclusion: It can be concluded from the experimental data that the biodegradation using the Fungi granules is a very efficient and thus promising technique for treatment of wastewaters containing phenolic compounds.

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AR-SA MicrosoftInternetExplorer4 Background and Objectives: Aerobic sludge granulation is an advanced phenomenonin which its mechanisms have not been understood. Granulation can be a promising and novel biological wastewater treatment technology to eliminate organic and inorganic materials in future. High salinity is a parameter which leads to plasmolisatian and reduction of the cell activity. This could be a problem for biological treatment of the saline wastewater. Aerobic granule was formed and investigated during this study.
Materials and Methods: This study is an intervention study on the treatment of wastewater with 500-10000 mg/L concentration of NaCl by sequencing batch reactor. Asynthesized wastewater including nutrient required for microorganism's growth was prepared. Input and output pH and EC were measured. Range of pH and DO varied between 7-8, and 2-5 mg/L, respectively. SEM technology was used to identify graduals properties.
Results: In terms of color, granules divided into two groups of light brown and black. Granule ranged in 3-7mm with the sediment velocity of 0.9-1.35 m/s and density of 32-60 g/L.Properties of granules were varied. Filamentous bacteria and fungi were dominant in some granules. However non filamentous bacteria were dominant in others. EDX analysis indicated the presence of Ca and PO₄.
Conclusion: Granules with non filamentous bacterial were compact and settled faster. Presence of different concentrations of salinity leaded to plasmolysis of the bacterial cells and increased concentrations of EPS  in the system as a result  of which granulation accelerated.

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A MicrosoftInternetExplorer4 Background and Objectives: Colored wastewaters are known as one of the most important sources of environmental pollutants. Having toxic chemicals and aesthetic problems has made treatment of these wastewaters very crucial. So far a number of methods such as electrochemical treatment, coagulation and flocculation, and adsorption have been used for treatment of textile industries wastewater. Hence,  the efficiency of zero-valent iron powder in the presence of UV light and hydrogen peroxide to remove Acid Orange 7 and Reactive Black 5 from the synthetic solutions was investigated.
Materials and Methods: Conducting all experiments in a batch reactor, we examined different parameters including initial concentration of the color (25, 50, 75 mg/L), contact time (30,  60, 120 min), pH (3, 7, 11), the amount of iron powder (0.6, 1.3,  2  g/l), and hydrogen peroxide concentration (10, 15, 20  ml/l).
Result: The results showed that dye removal efficiency was increased by increasing contact time, the amount of iron powder and hydrogen peroxide concentration. On the other hand, with the increasing pH and initial concentration of dye, removal efficiency decreased in both AO7and RB5 dyes.
Conclusion: We found that the integrated ZVI/UV/H₂O₂ method has  high efficiency in removing azo dyes Acid Orange 7 and Reactive Black 5.

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Background and objectives: Formaldehyde is one of the compounds widely used in various industries hence, its discharge into the effluent is unavoidable. Exposure to formaldehyde has a significant health effects. To prevent these issues, treatment of wastewater containing formaldehyde is necessary. The purpose of this study was to determine the performance of aerobic sequencing batch reactor (SBR) in removing formaldehyde from wastewater. Methods: We used a SBR having a total volume of 6.15 liters and an effective volume of 4 liters. The formaldehyde and COD removal efficiency of SBR was evaluated by applying loading rate of 0.031 to 0.156 kgCOD/m3.h. Four cycles of 6, 8, 10, and 12 hours were considered to investigate retention time effect onto the reactor efficiency. Results: Acclimation of microorganism with formaldehyde was achieved after about 30 days. We found that a retention time lower than an hour is not enough for achieving an acceptable efficiency. The maximum removal efficiency (90.52% for COD and 95.32% for formaldehyde) was observed at organic loading rate of 0.031 kg COD/m3.h and 12 hour retention time. The removal efficiency decreased to 46.44% for COD and 69.12%, for formaldehyde with increasing the organic loading rate to 0.156 kg COD/m3.h. The maximum concentration of MLSS was measured 2863 mg / L at organic loading rate of 0.091 kg COD/m3.h. Conclusion: The results showed that SBR could be applied as a practical, effective, and reliable technology for treatment of wastewater containing formaldehyde.

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Background and Objectives: Conventional methods of leachate treatment are inefficient due to high pollution loads and characteristics of the leachate. In recent years, an integrated method has been developed considerably. The aim of this research was to evaluate the effect of powdered activated carbon on the treatment of landfill leachate of Kermanshah City by a columnar aerobic sequencing batch reactor.

Materials and Methods: This study was carried out in three reactors having a total volume of 2000 mL and each having an effective volume of 600 mL in the bench scale. To the reactors 2 and 3 that were similar from environmental conditions and operation point of view with reactor 1 (with no carbon powder), 5 and 10 g/L of PAC were added, respectively. The effects of different doses of PAC (0, 5, 10 g/L) and hydraulic detention times (HRT = 48, 96, 144 h) were investigated in order to remove the Chemical Oxygen Demand (COD) and ammonia nitrogen (NH₃-N) from the leachate. The efficiency was investigated using two -way ANOVA test in SPSS software (Ver. 16).

Results: The results of two-way ANOVA showed that there was a significant difference (P-value=0.001) between the removal efficiency of COD and NH₃–N at different HRTs with different doses of PAC. The highest removal efficiency achieved at HRT=144 h for COD and NH₃-N was in Reactor 1 were 50.11 ± 4.42 and 19.85 ± 1.49%; in reactor 2: 55.67 ± 1.6 and 25.7 ± 0.89%; and in reactor 3: 58.02 ± 3.99and 25.48 ± 1.7%, respectively.

Conclusion: It can be concluded that the combination of biological - activated carbon compared with the biological process, can remove COD and NH₃–N of strong sewages such as landfill leachate, although achieving standard treatments using this method is not possible.