Iranian Journal of

Backgrounds and Objectives: Direct biodegradation of landfill leachate is too difficult because of high concentrations of COD and NH3 and also the presence of toxic compounds. The main objective of this study was to application of Strurvite precipitation as a pretreatment stage, in order to remove inhibitors of biodegradation before the batch decant activated sludge process with addition of powdered activated carbon (PAC).
Materials and Methods: Strurvite precipitated leachate was introduced to a bench scale batch decant activated sludge reactor with hydraulic retention times of 6 and 12 hour. PAC was added to aeration tank directly at the rate of 3.5 g/L.
Results:TCOD, SCOD, NH3 and P removal efficiency with addition of PAC in HRT of 6 h were 90,87, 98.3 and 94 % respectively and 96, 95, 99.2 and 98.7 5 in HRT of 12 h.
Concusion:According to obtained data from this work, it can be concluded that Strurvite precipitation before batch decant activated sludge process and simultaneous addition of PAC is promising technology for leachate treatment and can meet effluent standards for discharge to the receiving waters.

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.

Backgrounds and Objectives: As industries are developed, human uses of the energy in the huge scale and release the loss  energy in the form of electromagnetic radiation such as infrared into the environment, that it could affect on the man health. According to the available standards, if the IR-A could be controlled and consequently health of workers could be provided, it would reduce the total industrial expenses.
Materials and Methods: To control this radiation, it is necessary to measure it and compare the results with the available standards. Hence, in this study, we try to  measure this radiation in a unit of industy. For this porpuse the unit of steel company that settled in southeast of ahvaz is selected.
Results: The determinations were done every month during one year in all selected units. These results are compared with the available standards, and finally the differences are statistically evaluated by some suitable statistical methods. For measuring the dispersal of ray in the diffrent height. bat hard data compared with ACGIH standard and SPSS software is used for changing Radiation.
Conclusion:  The  average amount of IR-A  at  this  industrial  unit  is  1.18 mW/cm2  which  is more than the standard value in such industries ,and based on our fouding the natural solar source of this radiation increases such effects in out-door work places.

Backgrounds and Objectives:Propylene glycol is applied in many industries as raw material and can be released to the environment through wastewater of such industries. The biological treatment of solutions containing high concentration of propylene glycol is difficult and some problems can be observed during this process. The main objective of this study was the investigation of electrochemical degradation of propylene glycol and the parameters influencing on improving removal efficiency.
Materials and Methods: In this study the degradation of propylene glycol was made by passing an electrical current though the synthetic wastewater containing propylene glycol. In order to investigate this process several types of electrode with applied voltage ranging between 5 to 50 V was used. Due to the effect of NaCl concentration on removal efficiency which was mentioned in the literature, the experiment was performed for different NaCl concentrations.
Results: In optimum condition, the maximum removal efficiency of propylene glycol (based onCOD) was obtained equal to 90%. The results showed that rising applied voltage, NaCl concentrationand retention time increase the removal efficiency. The optimum retention time was obtained equalto 50 min. The maximum removal was obtained when aluminum electrode was used. It can beattributed to the production of coagulant material such as Al+3 during this process.
Conclusion: The results revealed that this process can be useful for treating the industrial wastewatercontaining propylene glycol.

Backgrounds and Objectives: Untreated leachate is discharging into the environment in the many countries of worldwide. Leachate treatment methods have not been unified so far due to variable composition of leachate. Moreover, the uncontrolled management of leachate, cause many environmental dissociates. The aims of this study apply the Fenton process to decrease the pollutants of Kerman leachate.
Materials and Methods: Rawleachatewas obtained fromcompactor vehicles used for the collection of Kerman city solid waste, before final disposal. In order to removal of biodegradable organic compounds, a rector was built based on characteristics of landfill Kerman city and raw leachate underwent anaerobic treatment in this pilot. In the next stage, treated leachate in the pilot, was affected by Fenton process. The optimized parameters in Fenton process including pH, reaction time and dosage of H2O2 and Fe2+ were also studied.
Results: The results showed that TSS, BOD5 and COD decrease to 62*, 96*and 89*, respectively, after 60 days treatment in the pilot. BOD5/COD ratio also decreased from 0.6 to 0.2 in anaerobic treated leachate. In optimum condition (pH=3, reaction time=75 min, Fe2+=1400 mg/L and H2O2 = 2500 mg/L) maximum COD removal was 78 * by Fenton process. BOD5/COD ratio increased from 0.2 to 0.51 which showed an increase in biodegradability of leachate as a result of Fenton process.
Conclusion: anaerobic biologically treatment followed by Fenton processes could be assumed as an efficient process that could improved the leachate quality. Biological treatment to reduce leachate pollution alone was not enough. The most important Fenton process advantage is reduction of refractory and toxic leachate compounds and increasing leachate.s biodegradability.

Backgrounds and Objectives: Oil pollution can be generated as a result of spillage, leakage, discharge, exploration, production, refining, transport and storage of crude oil and fuels in the environment. Consequently, many researchers have developed and studied the chemical, physical and biological methods to degrade crude oil. Among them, the biological treatments are the most interesting as they are simple and economical methods. The aim of this study was to determine biokinetic coefficients of crude oil degradation by pseudomonas aerogenusa. This microorganism was isolated in our previous work.
Materials and Methods: In this study the bio-kinetic coefficients of crude oil biodegradation were evaluated. Pseudomonas aerogenusa bacteria which had been isolated from the soil sample taken from a gas station in our previous work were used in this study. This microorganism was cultured in the liquid medium containing crude oil as sole carbon source. Finally with determining the amount of microorganisms and crude oil concentration during biodegradation process, the bio-kinetic coefficients based on modified Monod equation were calculated.
Results: bio-kinetic coefficients obtained from laboratory studies are vital factors in industrial applications. As a result, the bio-kinetic study was performed to find bio-kinetic coefficients for biodegradation of crude oil using the isolated bacteria. The results showed that ,Y, k and were equal 0.107 , 0.882 , 9.39 and 169.3 respectively.
Coculusion:Our results showed that pseudomonas aerogenusa is usable for treatment of oily wastewaters in the full scale facility. Results of this study indicated bio kinetics confections.

Background and Objectives: Fluoride is widely used in industries such as manufacture of semiconductors, power plants, glass production etc and release to the environment via their effluents. The purpose of this sturdy was to compare the efficiency of low price adsorbents in fluoride removal from water.
Materials and Methods: The optimum values of pH, contact time and adsorbent dosage were determined and different concentrations of fluoride were experimented in lab scale conditions for bagasse, modified bagasse and chitosan. Then Langmuir and Freundlich coefficient were determined based on optimum conditions.
Results: The pH value of 7, contact time of 60 min and adsorbent dosage of 2 g/L were determined as optimum conditions for all three adsorbents. The most fluoride removal efficiency of 91% was obtained for modified bagasse in optimum conditions.
Conclusion: Based on data obtained in this study, it can be concluded that adsorption by modified bagasse is an efficient and reliable method for fluoride removal from liquid solutions.

Background and Objectives: Industrial processes are the major sources of environmental pollutants. Oil & gas processing are one of the industries which emitting several air pollution matters in to the atmosphere. The obtained results of CO₂ emission in one of the Gas Sweetening unit of Iranian south oil company based on the field and deskwork calculations is presented in this paper.
Materials and Methods: Fuel analysis method is the best method for CO₂ estimation from combustion sources. In this paper, CO₂ emission factor for gas sweetening plants is estimated based on this method.
Results: The obtained results showed that  total CO₂ emission in selected unit is about 922212/97 (kg/d) and CO₂ emissions for the separate parts of this unit are 579661/75, 12921/93 and 329629/29 for acid gas flare, gas flare and boilers respectively.
Conclusion: comparison between the separated parts of the studied units showed that emission of acid gas flare is higher than other sources (i.e about 63% of total CO₂ emission), and by using the EPA default CO₂ emission factors the CO₂ emitted 1/2 % lower than the actual emission in the mentioned unit.

Backgrounds and Objectives: Improvement of water quality standards and inability of mono layer filters in producing such quality caused researchers attended to multi layer filters. Due to specific characteristics of anthracite and leca can improve removal of organic materials and Surface over flow rate. The aim of this research was evaluation performance of dual media filters (anthracite/leca) in removing of organic materials and turbidity from Ahvaz Water treatment plant
Materials and Methods: In this study two pilots built for investigation of mono layer filter and dual media filter performance. The researcher used sand in structure's media of mono layer filter and composition of anthracite, sand and leca in structure's media of dual media filter, respectively.  In this study single and dual layer filter pilot examined in term of organic matter and turbidity removal efficiency. 
Results: Results indicated that removal of organic matter by single layer filter (sand), dual media filter (anthracite,  and sand), dual media filter (leca and sand) was 7%,12%,4/2% respectively. And also Turbidity removal by single layer filter(sand), dual media filter (anthracite and sand), dual media filter (leca and sand) was also  69%, 80%, 74% respectively.
Conclusion: Results of this study showed that upgrading of Single layer to dual layer with anthracite and leca media can‘t show a significant affect in TOC removal.

Background: FMEA is one of the best known system safety techniques widely used as an identification tool. The purpose of this study was to apply FMEA method to identify and assess the risks posed by power lines in a residential area is Hasyrabad, Ahwaz. Materials and Methods: First, we identified the power line process and the equipment involved. Later, we determined the failure modes of equipment, which leads to the risk in the area studied. In order to measure the magnetic field lines, we used 3D EMF TESTER. Risks identified were scored based on the FMEA and for each case we calculated RPN. Then, with the help of SPSS software, we calculated level of risk and the cases identified were prioritized and analyzed based on the risk level. Results: The highest RPN values were associated with health risks and all risks involved in this group are at emergency conditions. It was revealed that wires (loss of privacy) and power transmission line (non-compliance with privacy standards) had highest value (RPN 360) and disconnect switch had lowest value (RPN 60). Conclusion: Due to the high risk in most cases, control measures were proposed based on the expertise in the safety-related equipment, training operators, and regulatory measures in order to reduce the level of risk.

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.

Background & Objectives: Entering LAS through the wastewater plant’s effluent to water resources causes taste and odor changes, aquatics death, oxygen transfer limitation, and disorders in water treatment processes. Therefore, the study objective was to determine optimum conditions for fenton oxidation process to remove linear alkyl benzene sulfonate from aqueous environments using taguchi method and its requirement evaluation for additional treatment of Biolac effluent. Materials &Methods: LAS removal using Fenton oxidation was evaluated in a 500 mL laboratory-scale batch reactor. In order to save the costs, to determine the optimum conditions of the Fenton oxidation, 25 runs were computed using Taghuchi method by Minitab 16 software. Sampling and required tests were performed based on standard methods examination for water and wastewater. For evaluation of Biolac process sufficiency in LAS removal, biolac efficiency in Urmia Wastewater Treatment Plant was studied in 2012. Results: Based on the LAS removal and chemicals required, Minitab software (Ver. 16) recommended the optimum conditions of Fenton oxidation at 900 mg/L H2O2, 170 mg/L Ferrous ion, pH of 4, and reaction time of 20 minutes. It was found that the Fenton oxidation for LAS removal had 86.5% efficiency under optimum condithions and it was second order reaction with the rate coefficient of 0.0152 L/mg.min. Biolac process does not need any additional treatment due to meeting LAS standard in municipal wastewater treatment. Thus, this process decreased annually mean LAS from 5.28 mg/L to 0.734 mg/L in municipal wastewater. Conclusion: Although the Fenton oxidation appears as a chemical process with high efficiency in the removal of LAS, the low efficiency of COD corresponding to the LAS indicated partial decomposition of linear alkyl benzene sulfonate by Fenton oxidation.