N Jaafarzadeh Haghighifard, M.m Mehrabani Ardekani, R Nabizadeh Nodehi, A.r Yazdanbakhsh,
Volume 2, Issue 1 (7-2009)
Abstract
Backgrounds and Objectives: in recent years, mobile bed biological reactors have been used progressively for municipal and industrial wastewaters treatment. Dissented experiment is a trial that significant changes will accrue for influent variables in the process, and generally used for identification of the effective factors and optimization of the process. The scope of this study was determination of the optimized conditions for the MBBR process by using of Taguchi method.
Materials and Methods: Reactor start up was done by using of the recycled activated sludge from Ahwaz wastewater treatment plant. After that and passing the acclimation period, with hydraulic residence time equal to 9 hours matched for 1000, 2000 and 3000 mg/l based on COD respectively, for optimization determination of the acclimated microbial growth, the variables change (pH, nitrogen source, chemical oxygen demand and salinity) were determined in 9 steps, and all of the results were analyzed by Qualitek -4 (w32b).
Results:In this study, organic load removal based on COD was 97% and best optimized condition for MBBR were (inf. COD=1000 mg/l, pH= 8, salinity = 5% and the Nitrogen source= NH4CL)
Conclusion: Based on our finding, we may conclude that Taguchi method is on of the appropriate procedure in determination the optimized condition for increasing removal efficiency of MBBR.
Alireza Chackoshian Khorasani, Mansour Mashreghi, Soheila Yaghmaei,
Volume 6, Issue 4 (3-2014)
Abstract
Background and Objectives: Optimization of mazut biocracking with different variables is one of the bioengineering applications in petroleum industry. The purpose of this study was to optimize biocracking of mazut by native microorganisms. Materials and Methods: To optimize mazut cracking, using Taguchi method we run 32 experiments using seven factors including amount of microbial inoculation, initial pH, surfactant, glucose, phosphor source, nitrogen source and sea salt each of them with four levels and factor of microorganism type with two levels for design of experiment using that 32 experiments were designed by them. Results: Results showed that microbial mixture, 0.016 OD600 microbial inoculations, pH 8.3, Tween80 concentration of 2 g/L, glucose concentration of 4 g/L, phosphate concentration of 5 g/L, ammonium concentration of 9 g/L and sea salt concentration of 0.5 g/L were optimized conditions for biocracking of mazut process. Conclusion: Optimized level for each factor was not essentially inevitably the highest or the lowest level. Based on the analysis of variance, phosphor source with 15.8% and pH with 14.8% had the highest effect among other factors however overally, error factor with 31.6% had the highest influence. Amount of microbial inoculation with 0.63% had the lowest effect on optimizing biocracking of mazut.
S. Jorfi, A. Rezaee, N. Jaafarzadeh Haghighifard, G.a Moheb-Ali,
Volume 7, Issue 3 (5-2014)
Abstract
Background and objectives: Because of problems dealing with bioremediation including being time consuming, low efficiency and toxicity to biota, application of advanced oxidation processes with higher efficiency and shorter remediation time have been considered for removal of hydrophobic hydrocarbons from contaminated soils. A great interest has been directed to Fenton oxidation because of its simplicity and high oxidation potential. The objective of this study was to determine the Fenton-like oxidation efficiency for pyrene removal from soil using iron nano oxides and Fe2+. Material and Methods: The H2O2/Fe molar ratios of unadjusted with native Fe content of soil, 10, and 20 H2O2 concentrations of 0 – 500 mM pH 3, 5, and 7 and soil samples containing Fe2+, native iron and iron nano oxides were investigated for removal of 100 mg/kg pyrene according to Taguchi experimental design. Results: Fe2+, H2O2/Fe molar ratio of 20, pH 3 and H2O2 concentration of 500 mM were determined as optimum conditions. Under optimum conditions, S/N ratio increased to 39.322 and the pyrne removal reached to 86 % for Fe2+ and 83 % for Fe3+ respectively, after 2 hours of reaction time and pH 3. Conclusion: Fenton oxidation using iron nano oxides under defined optimum conditions and neutral pH, can be a suitable alternative to conventional Fenton for remediation of soils contaminated with pyrene.
