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Advances in Environmental Technology - Volume:3 Issue: 3, Summer 2017

Advances in Environmental Technology
Volume:3 Issue: 3, Summer 2017

  • تاریخ انتشار: 1396/07/07
  • تعداد عناوین: 6
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  • Mina Salari, Seyed Ahmad Ataei *, Fereshteh Bakhtiyari Pages 133-137
    Sequencing batch reactor (SBR) technology has found many applications in industrial wastewater treatment in recent years. The aim of this study was to determine the optimal time for a cycle of the sequencing batch reactor (SBR) and evaluate the performance of a SBR for petrochemical wastewater treatment in that cycle time. The reactor was operated with a suspended biomass configuration under aerobic conditions. Carbon removal and operating parameters such as pH, temperature and dissolved oxygen (DO) were monitored during the wastewater treatment. The SBR was run at different cycle times and amongst the cycle times tested, the best performance was obtained with a 7 h cycle time composed of a fill time of 15min, reaction of 6 h, settling of 30 min, and withdrawal of 15 min. The SBR with the determined cycle time was used to study the treatment of wastewater with various organic loading rates (12.88 gr COD/L.d, 18.02 gr COD/L.d and 31.39 gr COD/L.d). The SBR performance was evaluated by chemical oxygen demand (COD), total solids (TS) total suspended solids (TSS) removal efficiencies. During the shock loading tests, the maximum COD, TS and TSS removal efficiencies were 84%, 67% and 92%, respectively.
    Keywords: Sequencing Batch Reactor (SBR), Petrochemical wastewater, Optimum operation time
  • Fatemeh Tangestani, Mohammad Hasan Mallah, Abbas Rashidi *, Rohollah Habibzadeh Pages 139-149
    In this study, the adsorption of cesium, strontium, and rubidium radionuclides by ferritin magmolecules in a batch system was investigated under different experimental conditions. The experiments were conducted in a pilot plant that involved the contactor unit and the magnetic separator unit. The impact of the pollutant concentrations, adsorbent concentration, and pH on the efficiency of the process were investigated thoroughly. The maximum recovery of radionuclides in the studied domain were 57.05%, 85.42% and 71.82% for Cs, Sr2 and Rb ,respectively, in which the pollutant concentration was 363.63 mg/l, the adsorbent concentration was 0.011 g/l, and the pH was 7.5. The results showed that the ferritin adsorbent in the magmolecular process manifested a higher efficiency in adsorbing the bivalent ions of strontium compared to the univalent ions of cesium and rubidium. Furthermore, the results were statistically analyzed and the model and residual plots of each radionuclide were presented. The results also signified relationships between the independent variables and recovery.
    Keywords: cesium, ferritin, Strontium, rubidium, Magmolecular process
  • Nasrin Oroujzadeh* Pages 151-158
    Two new Chitosan-based nanocomposite films were prepared: Chitosan /7% Ag nanoparticles (NPs) (NC1) and Chitosan/7% Ag NPs/5%Carbacylamidophosphate(NC2), in which the carbacylamidophosphate derivitive is N-Nicotinyl-N′,N″- bis(hexamethylenyl) phosphorictriamide (NHE) with the formula: C5H4NC(O)NHP(O)(NC6H12)2. X-ray Powder Diffraction (XRD), Field Emission Scanning Electron Microscopy (FE-SEM) and Energy Dispersive X-ray Spectroscopy (EDS) methods were used to characterize and confirm the prepared frameworkrs. XRD graph of the two nanocomposites showed all the characteristic peaks of NHE, Ag NPs, and chitosan, indicating the fact that the preparing process has not made any changes in the phases of the nanocomposites components. All the SEM micrographs and EDS analysis results also confirmed the desired structures. To study the effect of the additive NHE on the antibacterial activity of the films, in vitro antibacterial tests were done on the prepared nanocomposites against two Gram-positive (Staphylococcus aureus, Bacillus cereus) and two Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa) in Brain-Heart Infusion(BHI) medium. Results showed that the antibacterial effects of the nanocomposite containing NHE on each of the four bacteria is stronger than those for the nanocomposite without NHE.
    Keywords: Carbacylamidophosphate, Chitosan, Ag Nanoparticles, Nanocomposite, Antibacterial activity
  • Najme Boosaeidi, Alireza Pourkhabbaz, Moslem Jahani * Pages 159-167
    Hexavalent chromium, a highly toxic metal ion employed in industrial activities, is considered as a first priority pollutant. In this study, the capsule walls of the boll of cotton (cotton waste, CW) and the waste obtained from pruning barberry bushes (barberry waste, BW) were investigated as cheap and locally available adsorbents for Cr (VI) removal. The adsorption behavior, equilibrium, and kinetic properties have been studied through batch experiments. Specifically, the sample pH showed a significant effect and an initial pH of 2.0 was most favorable for the effective removal of chromium. The equilibrium adsorption data were well fitted to the Langmuir adsorption equation with the maximum adsorption capacities of 20.7and 15.5mg/gfor CW and BW, respectively. The kinetic evaluations showed a rapid rate of adsorption (within 10 min) that followed the pseudo-second order kinetic model. In competitive adsorption tests, Cl̶ had the least effect on the adsorption efficiency of Cr (VI), especially for CW. The results indicate the potential for the application of the studied agricultural wastes as adsorbents to reduce Cr (VI) concentration in aqueous samples.
    Keywords: Cotton plant, Barberry bushes, Hexavalent chromium, Bio-sorption
  • Fatemeh Ardestani *, Ali Shokuhi Rad Pages 169-175
    The lignocellulosic wastes produced in food industries are suitable raw materials for the production of biological products. In this study, the solid state fermentation of Aspergillus flavus on lignocellulosic wastes was evaluated for microbial protein production. The fraction of the full factorial method was applied for experiment design and process optimization. The results analysis was performed through signal to noise statistical index using the Taguchi approach via Qualitek-4 software. Glycine, ammonium sulfate and iron sulfate concentration as well as temperature were considered as effective parameters. The maximum biomass concentration of 45.7 g/kg containing 55.75% (w/w) pure protein was obtained at optimal conditions including 0.5, 0.02, and 2 g/kg of ammonium sulfate, iron sulfate and glycine, respectively, at 25 °C. Ammonium sulfate (33.78% (w/w) contribution) and culture temperature (31.98% contribution) were evaluated as the most effective factors on biomass and microbial protein production. The highest interaction occurred between ammonium sulfate and glycine with an interaction severity index of 50.03%. The low deviation of 3.94% was determined between optimum theoretical biomass concentration (43.9 g/kg) and the experimentally measured one (45.7 g/kg). Due to the high protein content of 55.75% (w/w), Aspergillus flavus was introduced as a suitable strain for industrial protein production.
    Keywords: Aspergillus flavus, Bioremediation, Lignocellulosic wastes, Microbial protein, Solid-state fermentation
  • Maryam Pazoki *, Reza Ghasemzade, Parisa Ziaee Pages 177-184
    Different numerical and analytical models are presently available that provide the tools to predict pollutant and water transfer processes between the soil surface and the groundwater level. Among the existing models, the Hydrus-1D model has been used for years in the prediction of water and pollutants transfer in the unsaturated zone. The main purpose of this paper was to model the movement of the landfill leachate in the soil at the Aradkouh landfill and predict the changes in nitrogen and phosphorus concentration in the leachate at different depths. Two pilots were used in this study, one included the local soil and the other contained local soil with Vetiver grass (Chrysopogon zizanioides). After its initial purification, the resultant leachate entered the pilot and was collected after passing through the soil. Finally, the flow of the leachate movement as well as the nitrogen and phosphorus concentration changes in soil were modeled by using Hydrus-1D. The prediction model for the phosphate and nitrogen concentration changes at different depths showed that the best results were obtained in the surface charge of 0.12 m3/m2.week and by the pilot with the Vetiver grass. The results showed that the use of Vetiver grass in surface purification increased the efficiency of the purification.
    Keywords: Hydrus-1D, Leachate, low rate, Municipal solid waste