[Modified Fenton oxidation of pyrene in contaminated soils using iron nano oxides]

Problems related to conventional Fenton oxidation, including neccesity of having a low pH and production of considerable amounts of sludge, have prompted researchers to consider chelating agents to improve the pH operating range and iron nano-oxide particles to reduce excess sludge. The main objective of this study was to remove pyrene from contaminated soils by a modified Fenton oxidation method at neutral pH. Experiments were conducted using various concentrations of H2O2 [0-500 mM], iron nano-oxides [0-60 mM], reaction times [0.5-24 hours] and several chelating agents, namely, sodium pyrophosphate, ethylene diamine tetra-acetic acid, sodium citrate, fulvic and humic acids, to eliminate pyrene from soil [concentrations of 100-500 mg/kg]. The efficiency of removal of pyrene at an initial concentration of 100 mg/kg was 99% at the following reaction conditions: H2O2 and iron nano-oxide concentrations of 300 mM and 30 mM, respectively; pH=3; and a reaction time of 6 hours. The initial pyrene concentration of 100 mg/kg decreased to 7 mg/kg at optimum conditions using sodium pyrophosphate as the chelating agent at pH 7. The modified Fenton oxidation method, using iron nano-oxide at optimum conditions as defined in this research, is an efficient alternative for chemical remediation or pre-treatment of soils contaminated with pyrene at neutral pH

Performance of a land treatment system and vetiver plant for advanced treatment of ahvazwest Municipal wastewater treatment plant effluent

Background: During the last decades efforts related to waste water treatment, has improved significantly in Different places of our country with various climate conditions. To reach this aim using systems are considered that have appropriate applications technically and economically . One of the low cost and native options is using Land-plant system for advanced waste water treatment. The aim of this study was determination of efficiency of local soil of Ahvaz and vetiver plant tothe final reduce the organic load from Municipal wastewater treatment

Materials and Methods: In order to, a pilot including three Lysimeter swere installed in Ahvaz West wastewater treatment plant. ThreeLysimeter were utilized that local soil was used in one of them, local soil with vetiver plant were used in the other one and soil artificial arrangement local soil, silica sand [0.5-1mm], sand [15-30mm] was used in third Lysimeter. The effluent was transferred from Secondary settling outlet by pump for system that slow current in three filtration rate of 0.2, 0.6, 1 ml/min and three replication in each rate was used

Results: The average removal efficiency of BOD5 and COD output from three Lysimeter local soil with vetiver plant, local soil without vetiver plant and soil artificial arrangement for filtration rate of 0.2 ml/min were;73.27%, 68.39%,58.91%, 50.34%, 37.62% and 35.9%.For filtration rate of 0.6 ml/min were;49.47%,41.97%, 43.16, 28.31%, 33/68% and 25/55%.For filtration rate of 0.6ml/min; 26.44%,31.44%, 19.95,17.81%, 12.06% and 14.79%, respectively

Conclusion: The results from this study showed that the best removing percent was assigned to local soil with vetiver plant lysimeter in 0.2 ml/min current. Based on the results of this study, it can be concluded that a land- plant system as advanced treatment had the ability to meet effluent discharge permit limits and was an economical replacement for stabilization ponds and mechanical treatment options

Fluoride removal from water by adsorption using Bagasse, Modified Bagasse and Chitosan

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. 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. 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. 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

[Determination and emission factories of SO[2], CO[2], CO, NO, NO[]2, NO[x] gases in the fanavaran petrochemical]

Fanavaran petrochemical company is located on the shore of Persian Gulf on west south of Iran, Imam Khomeini Bandar, petrochemical special economic zone with of 25 hectares area. Two units of this company, methanol unit with production capacity 1000000 tons/ years andmonoxide carbon unit with 140000 tons/years were studied for determination and emission factories of SO[2], CO[2], CO, NO, NO[2], NO[x] Gases. With attention to project goals, for implementation of this project 14 months took into from April 2008 till June2009. For goals provide of mentioned research on this basis, 32 case sampling were done from 3 emission sources by using of direct reading device of gas concentration according to standard methods of United State Environmental Protection Agency Results of the study indicate that concentration of issued pollutant gases from these units is in the level lower than Iran department of environment standard level. The total amount of emission Factory of SO[2], CO[2], CO, NO, NO[2], NO[x] gases diffused from these units are11.7 X 10[-6], 81/8 X 10[-6], 0.14 X 10[-6], 431.5 X 10[-6], 19.2 X 10[-6], 681.2 X 10[-6] kg /tons million production in a year respectively. Parameters which optimization is performed in accordance with them, include of additional air percentage, exit air temperature from pre heater, and fuel type, in fact with regarding these 3 factor's. effects, the work is done in a manner that the amount of pollutants diffusion is near to minimum and the selected best fuel

[Evaluation of electrochemical treatment in degradation of wastewater contaminated by propylene glycol]

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. 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. In optimum condition, the maximum removal efficiency of propylene glycol [based on COD] was obtained equal to 90%. The results showed that rising applied voltage, NaCl concentration and retention time increase the removal efficiency. The optimum retention time was obtained equal to 50 min. The maximum removal was obtained when aluminum electrode was used. It can be attributed to the production of coagulant material such as Al[+3] during this process. The results revealed that this process can be useful for treating the industrial wastewater containing propylene glycol

Optimization of bacteriological quality of biosolids by lime addition

Lack of well-stabilized biosolids is a basic problem for many municipal wastewater treatment plants in Iran. Disposed biosolids from west Ahvaz wastewater treatment plant were generally used for agricultural activities. Initial evidence showed that these biosolids were untreated and had the potential to transmit many pollutants to the environment and create hazards for public health, although anaerobic digester was selected for this wastewater treatment plant. The main objective of this research was to evaluate and optimize the bacteriological quality of biosolids by lime addition in west Ahvaz wastewater treatment plant. The stability and reuse potential of biosolids from existing anaerobic digester and lime added biosolids were investigated. Lime addition to biosolids was performed in the reactor with 30 L capacity. Averge amounts of fecal coliforms and viable helminthes ova in disposal biosolids from anaerobic digester were 1.3'1015 MPN / g of dry solids and 314 ova / 4 g of dry solids, respectively. By lime addition with the ratio about 0.265 g Ca [OH]2 per g of dry solids, pH was not dropped under 12 and growth of fecal coliform was not detected after 30 days. In this regard, discharged biosolids from this plant was unstable and very dangerous for reuse or disposal. Lime addition could stabilize the biosolids and reduce fecal coliforms more than 99.99% and had concordance with class B of United State Environmental Protection Agency criteria. Lime-stabilized biosolids could hence be well used for reconditioning the poor soil and for covering of solid waste landfill-sites

[Leachate treatment by batch decant activated sludge process and powdered activated carbon addition]

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]. 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. 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. 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

[Optimization of moving bed bioflim reactor using taguchi method]

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. 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/1 based on COD respectively, for optimization determination of the acclimated microbial growth, the variables change [p[H], nitrogen source, chemical oxygen demand and salinity] were determined in 9 steps, and all of the results were analyzed by Qualitek -4 [w32b]. In this study, organic load removal based on COD was 97% and best optimized condition for MBBR were [inf. COD 1000 mg/1, pH= 8, salinity = 5% and the Nitrogen source= NH4CL]. 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

[Determination of near infrared radiation[IR-A] at work unit in one of the Iran steel industries]

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. 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 industry. For this porpuse the unit of steel company that settled in southeast of Ahvaz is selected. 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 For measuring the dispersal of ray in the different height, bat hard data compared with ACGIH standard and SPSS software is used for changing Radiation. 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 founding the natural solar source of this radiation increases such effects in out-door work places

Developing a water quality management model for Karun and Dez rivers

The Karun and Dez rivers basin are the largest rivers basin in Iran which are situated in the south west of the country. Karun River originates from Zagros mountain ranges and passing through Khuzestan plain, reaches the Persian Gulf Several cities lie along its path of them the most important is Ahvaz, the center of Khuzestan province. To achieve water quality goals in Karun and Dez rivers, a water quality management model has been developed through the GIS approach and a mathematical water quality model. In Karun and Dez rivers, water quality has decreased due to heavy pollution loads from Khuzestan province cities and surrounding areas. In this survey, pollution sources, land use, geographic features and measured water quality data of the river basin were incorporated into the Arc-view geographic information system database. With the database, the model calculated management type and cost for each management project in the river basin. Until now, river management policy for polluted rivers in Iran has been first of all to get penalties from pollution sources and secondarily, to construct treatment plants for the pollution sources whose wastewater is released untreated and for which the wastewater quality goal of the Iranian Department of the Environment is not met. Different management projects with a time program were proposed and they were compared with the results of the river quality without any management approach. It became clear that the results based on the management approach were much better than those for the unmanaged condition from the viewpoint of the achievement of water quality goals and cost optimization

Effects of wastewater stabilization pond effluent on agricultural crops

Wastewater reclamation and reuse is one of the best alternatives for compensating water shortages. Water supply and environmental conservation can be met through wastewater reclamation. Principally, treated wastewater is a reliable water resource, especially for periodic droughts and in arid areas. This study designed and implemented to investigate the full scale application of effluent for irrigation use. A major objective of this study is to assess on health effects and feasibility of crop irrigation by using stabilization ponds effluent of southern Hovaizeh Wastewater Treatment Plant located in Khuzestan Province. Two experimental plots of about 0.5 ha. were constructed. One of the plots irrigated by stabilization pond effluent and the other irrigated by Nisan River water. Basic parameters in two plots such as type of cultivated crops, amount of fertilizer use and lack of soil contamination have been similar in both. The only difference was the type of water applied for irrigation of agricultural crops. It was shown that high salinity of soil reduced the growth rate of agricultural crops. So, removing salinity from area should be performed before cultivation. Results gained on agricultural crops growth in two studied plots showed the growth rate and quality of crops were increased by using of stabilization pond effluent in comparison with Nissan River water