Aims: The purpose of this study was to use a combinational process of catalytic oxidation of hydrogen peroxide (CWPO) and activated carbon for improving the removal efficiency of organic matter. Materials and Methods: The effect of the operational parameters such as residence time (30 - 90 minutes), reaction temperature (100-300°C) in the pressure 10 bar, and catalytic iron concentration were investigated. The effect of the catalytic method, catalytic wet peroxide oxidation (CWPO), along with the absorption process, on granular activated carbon (GAC), powdered activated carbon (PAC), PAC/Cl ₂ , and GAC/Fe were considered; oxygen is used to supply pressure and H ₂ O ₂ is applied as the main oxidant in various concentrations. Results: The removal efficiency of the chemical oxygen demand (COD) was over 35%, obtained in one hour of retention time, with the wet air oxidation (WAO) process, and the removal efficiencies of GAC, PAC, and PAC/Cl ₂ , at a temperature of 300°C, and activated carbon concentration of 2 g/l, were 43.4, 38.9, and 33.6%, respectively. Conclusion: These results indicate that the reaction temperature, residence time, and H₂O₂ dose are the most important factors affecting the degradation of organic matter. The GAC/Fe catalyst process had a higher efficiency than other absorbents for organic matter oxidation.

Aims: The goal of this study was the ultimate analysis and chemical composition of SW for energy recovery in Urmia city. Materials and Methods: A cross-sectional, descriptive study was done on municipal SW in Urmia city, northwest of Iran. The samples were collected during the four seasons of a year. Experiments were analyzed according to the American Society for testing and Materials (ASTM) Method D 5231-92. The chemical composition of the SW was calculated, to determine the quantity of produced biogas and heat value. Results: The findings showed that food waste percent had been 68.9%, carbon/nitrogen (C/N) 18.33, containing 10.4% ash and 54% moisture. The calculated chemical composition of organic SW was (C_27.7 H_43.1O_15.3 N₁S_0,065) with a heat value of the 2.2 × 10⁴ Kj/Kg. The produced methane and heat value of the biodegradable organic SW, chemical formula C _23.63 H _37.52 O _14.65 N ₁ S _0.069 , were 212 liters (151 g) and 9992 Kj per 1 Kg of SW. Conclusions: The recovery of SW energy through incineration was a better choice, due to the high heat value. However, it would produce more than 300 tons/day of greenhouse and poison gases, but land filling produced 200 tons/day of different gases. Thus, on the basis of the calculated SW composition in this research, it seemed that energy recovery through methane collection was a better option for this study area.

Aims: This study has been conducted to focus on the localization of the design parameters used for the design of wastewater treatment plants in a region of Iran. Materials and Methods: Three wastewater treatment plants were selected (as models) in a cold weather region of Iran. The main characteristics of the wastewater, such as, flow rate and its fluctuations, total solids, and the organic and nutrient contents, which play an important role in the design and operation of the wastewater treatment facilities, were measured for the selected plants during a year. Results: The averages of the design parameters for the investigated plants, including, biochemical oxygen demand (BOD ₅ ), chemical oxygen demand (COD), total suspended solids (TSS), volatile suspended solids (VSS), total Kjeldahl nitrogen (TKN), and total phosphorous (TP) were, 41, 60, 65, 47, 8.3, and 0.93 g/capita, respectively. Wastewater production was 177 lit/cap-day with a maximum and minimum coefficient of 1.76 and 0.29, respectively. Conclusions: Using design parameters based on the local characteristics and the real-world conditions of the wastewater, can result in more+operational efficiency in the wastewater plants. It is suggested that the results of this study can be applied to the design of wastewater facilities throughout Iran, with the same local conditions.

Aims: The objective of this study is to investigate the levels of lead (Pb) and cadmium (Cd) in the vegetables from the farms of Gorgan, Iran, and compare them with the permissible levels proposed by the Food and Agriculture Organization (FAO) and World Health Organization (WHO) standard. Materials and Methods: In this descriptive study, 40 samples of irrigating water and vegetables were collected, between the periods of August and December 2008. The Polarography apparatus was used to determine the amount of cadmium and lead after sample preparation. The level of significance was set at 5% for all the tests Result: The cadmium concentrations in spinach, garden cress, and radish were 0, 0.085, and 1.56 μg.kg ^-1 , respectively. The lead concentrations in spinach, garden cress, and Radish were 51.21, 40.13, and 87.27 μg.kg ^-1 , respectively. The cadmium concentration in irrigating water was not detectable with the Polarography apparatus. However, the lead concentration in water was 26.75 μg.kg ^-1. There was no significant variation between the cadmium levels in spinach and garden cress (P<0.05), while there was a significant difference between the amount of cadmium in radish and spinach and garden cress (P<0.05). Conclusion: All the vegetables and water contained Pb, although Cd was lower than the permissible levels proposed by FAO/WHO and might not cause health hazards to consumers.

Aims: This research was conducted to study the effects of the electrical conductivity (EC) of irrigation water and compost on the Cadmium (Cd) and Zinc (Zn) uptake by sunflower, Helianthus annuus. The transfer of Cd and Zn from soils close to the Zn mine, to the sunflower tissues, and the interactions between the two concerned metals, were also investigated. Materials and Methods: For this purpose, 10% weight/weight from municipal composts was applied to raw soils that were randomly collected from the mine region. Series analyses were also implemented by irrigation water, with EC values in the range of 0, 2, 4, and 6 dS/m. Results: The maximum uptake rate of Cd, with EC levels of 6 dS/m, in plant samples was 4.82 μg/g for the roots, 6.14 μg/g for the stems, and 5.4 μg/g for the leaves; and the maximum uptake of Zn, in plants irrigated with tap water, was 241 μg/g by the roots, 624 μg/g by the stems, and 229 μg/g by the leaves, respectively. Conclusions: Results showed that high EC levels of irrigation water increased Cd accumulation and decreased Zn accumulation in the shoots. The presence of high EC levels in irrigation water negatively affected biomass production by plants. Chlorine ion (Cl-) had a positive influence on Cd accumulation in the harvestable parts of the plant.

Aims: The objective of this study was to determine the malachite green (MG) concentration in trout tissue and the effluent water of fish farms, at one of the largest trout fishery industries in Iran. Materiels and Methods: Twelve samples of water and fish tissue were collected from fish farms placed at the upstream ends of two large rivers in the study area. The samples, after extraction, were analyzed with liquid chromatography-mass spectrometry (LC-MS). The effluent water samples were also analyzed by the spectrophotometric method after cloud point extraction using the anionic surfactant Triton X-100. Results: The concentration of malachite green in the fish samples ranged from 265.2 to 1663 μg/kg, which is more than the recommended maximum allowable concentration by the Codex standards. MG in the water samples ranged from 5.65 ng/L to 384 μg/L. The equivalent concentrations of MG in the two large rivers in the study area were 1.78 and 0.62 ng/L, and the total MG load for these two rivers, with a fish production rate of 10,000 tons per year, was around 644 kg/d. Conclusion: We concluded that the concentration of MG used as an antimicrobial chemical in trout fish tissues and water samples in this study were out of compliance with the existing standards. Therefore, the fish products of these farms could cause serious public health hazards, and the discharge of the effluent from these farms, without treatment, posed potential environmental problems.

Aims: This study has been conducted to assess air pollution, with respect to particulate matter less than 10 μm in diameter (PM ₁₀ ), sulfur dioxide (SO ₂ ), carbon monoxide (CO), nitrogen dioxide (NO ₂ ), hydrogen sulfide (H ₂ S), and the Air Quality Index (AQI), in a location at close proximity to the Bandar Abbas-Iran oil refinery. Materials and Methods: In this study, a location with close proximity to Bandar Abbas oil refinery was selected as the sampling station. The Air Sampling period was from June to September 2010. In order to assess PM ₁₀ concentrations, the samples were collected using a high volume sampler with fiberglass filters. To measure the concentrations of other air pollutants, including, SO ₂ , CO, H ₂ S, and NO ₂ , real-time instruments were used. With regard to air pollutant concentrations, the AQI values were calculated and for the wind rose, the effect of the oil refinery on Bandar Abbas was evaluated. Results: According to the results from the present study, PM ₁₀ , SO ₂ , nd NO ₂ concentrations were higher than the recommended values of the national ambient air standards. The maximum PM ₁₀ and SO ₂ concentrations and their resultant AQI values were observed in August and September, respectively. Other air pollutants had their highest concentrations in July and September, but in no case did they exceed the standard values. Conclusion: The three most significant outdoor problems with the air quality around Bandar Abbas oil refinery were the NO ₂ , SO ₂ , and PM ₁₀ levels.

Aims: In this study, the heavy metal contamination of consumable table salt, both unrefined and refined, was investigated. The provisional tolerable weekly intake (PTWI) of heavy metals just by edible salt, of the Isfahan population, was also estimated. Materials and Methods: Twenty samples of salt, including 15 refined and five unrefined were analyzed. Precision of the analysis was assured through repeated analysis of the five samples, which had a great demand in the city. The heavy metal content in the samples was analyzed with Flame Atomic Absorption Spectrometry (AAS) and Inductively Coupled Plasma (ICP). The PTWI of the metals was calculated by a formula and by using the Iranian average body weight. Results: The mean and standard deviations of cadmium (Cd), lead (Pb), arsenic (As), mercury (Hg), copper (Cu), and zinc (Zn), in refined table salts were 0.15 ± 0.02, 0.57 ± 0.1, 0.69 ± 0.09, 0.061 ± 0.008, 0.87 ± 0.11, and 6.34 ± 1.08 μg/g, and those in the unrefined ones were 0.16 ± 0.02, 0.61 ± 0.13, 0.63 ± 0.07, 0.058 ± 0.004, 0.86 ± 0.06, and 7.53 ± 2.93 μg/g, respectively. A PTWI via salt consumption was in the range of 0.8 - 3.1 percent. Conclusions: There was a significant difference between the heavy metal concentrations and their guideline values. Estimation of the health risk due to heavy metals was not possible as PTWI showed total intake of a metal by total food consumption during a week. Therefore, it was important to assess the public health risks arising from the presence of these toxic contaminants in the foods consumed by the population of Iran.

Aims: The objective of this study was to investigate an Upflow Anaerobic Sludge Blanket (UASB) reactor efficiency in treating municipal landfill leachate, under tropical temperature. Materials and Methods: A 30-liter pilot-scale UASB reactor was used to treat the municipal solid waste leachate, under tropical temperature, for 230 days. The reactor was inoculated with 10 liters of anaerobic sludge from an anaerobic digester, in an agro industry's wastewater treatment plant. The Volatile Suspended Solids (VSS) of sludge were 65 g/L, with volatile suspended solids to suspended solids (VSS/SS) ratio of 0.74. The reactor was operated in mesophilic (34 - 39°C) temperature. Results: After reaching a stable operation, the reactor was exposed to raw leachate, with mean chemical oxygen demand (COD) concentrations of 35 g/L. The leachate was diluted to 9 - 10 g/L at Organic Loading Rates (OLRs) of 2, 6, 12, 15 g COD/L.d and decreased again to 12 g COD/L.d, resulting in 45, 76, 84, 68, and 79% removal efficiency and increased again to 87% removal efficiency for COD, at Hydraulic Retention Times (HRTs) of 6, 1.6, 0.83, and 0.67 days, respectively, in the UASB. In the reactor used in this study, the heavy metals were removed by adsorption on biomass, and the maximum removal rate was 68% for Zinc (Zn). Conclusions: It was concluded that the optimum OLR for diluted leachate up to 10 g COD/l, was 12 g COD/L.d at an HRT of 0.67 day (16 hours).

Aims: There is limited data on the occurrence of E. Coli O157: H7 in water. Therefore, this study aims to detect E. Coli O157: H7 in the Water Treatment Plant (WTP). Materials and Methods: This cross-sectional study was conducted in Isfahan WTP, central of Iran. Immunological methods were implemented with anti-serum kits and the molecular method of reverse transcription-polymerase chain reaction (RT-PCR) was used to detect E. Coli O157: H7 in eight locations of the WTP; the sludge of the sedimentation basin and filter backwash water were also monitored. The survival of E. Coli O157: H7 in the sludge samples of the sedimentation basin was indicated by the formation of agglutination particles using the immunological method, and through indicator probes using the RT-PCR method. Results: E. Coli O157: H7 was not detected in the water samples from the WTP units. The removal percent of total coliforms (TC), fecal coliforms (FC), and Heterotrophic Plate Count (HPC), respectively, were as follows: 59.5, 49, and 54.8% in the sedimentation basin; 66, 45.8, and 57% in the ozonation system; 98.8, 98, and 78.8% in the filtration system; and 96, 100, 91% in the disinfection system. Conclusions: This study revealed the existence of the pathogenic coliform of E. Coli O157: H7 in the sludge of the sedimentation basin. The absence of E. Coli O157: H7 in the finished water indicated that the WTP units were able to eliminate these pathogenic bacteria before reaching the final units of the plant, including the filtration and disinfection systems.

Aims: In the present study, Vensim was used to simulate waste management system of Tehran, the capital of Iran, with the system dynamic approach. Materials and Methods: The environmental system dynamic modeling is one of the comprehensive simulation tools capable of simulating and analyzing complex systems. In this approach, the model is developed based on the existing realities and userâ€'comments. User participation to develop the model could increase the reliability of the results. Results: The simulation results revealed good conformity with the statistical data. Waste production prediction in the model with real data was more than 95%. Moreover, the effect of applying an encouraging policy for people to separate their waste was considered. The result indicated that applying a new policy, and the economic benefit through this policy would prevent getting a loan from the government after 20 years. Conclusions: It could be concluded that public participation in waste separation was an effective policy to help in the financial independence of the municipality in terms of urban waste management. Moreover, conformity between the simulation results and real data revealed an appropriate capability of the simulated model to predict Tehran waste generation.

Aims: The ability of raw and recycled multi- and single-walled carbon nanotubes (MWCNT and SWCNT) for xylene adsorption from aqueous solutions was evaluated. Materials and Methods: Batch adsorption experiments were conducted in 110 ml glass bottles. Gas chromatography-mass spectrometry was used for xylene measurement and the carbon nanotube characteristics were evaluated with the help of a transmission electron microscope. Results: With a carbon nanotube dose of 1 g/l, xylene concentration of 10 mg/l, pH 7, and a contact time of 10 minutes, the equilibrium adsorption capacity (q _e (mg/g)) of SWCNT was 9.2 mg/g, which was higher than that for MWCNT (8.9 mg/g). The SWCNT revealed a better performance for xylene sorption than the MWCNT. Results of a desorption study showed that xylene adsorbed onto the SWCNT and MWCNT can be easily desorbed at 105 ± 2°C. Conclusions: It is concluded that recycled carbon nanotubes on heating for the first time, show a better performance for xylene adsorption than when they are raw. The SWCNT are efficient as xylene adsorbents in an environmental pollution cleanup.

Aim: In this study the performance of a natural nanozeolite, modified with a cationic surfactant, on the adsorption of humic acid from water was investigated in a batch system. Materials and Methods: Clinoptilolite as a natural nanozeolite was modified with different doses of a cationic surfactant solution, hexadecyltrimethylammonium bromide (HDTMA-Br), at dosages from 0.5 to 10 g/l. The modified adsorbents were individually added to synthetic water samples containing a known amount of humic acid and put on the shaker for two hours, at room temperature. Humic acid (HA) concentrations, turbidity, and pH were measured before and after the adsorption process. Results: According to the results obtained, and based on the statistical analysis (Pearson correlation statistical test), there was a clear correlation between the cationic surfactant dosage and HA removal (P_value <0.001, r=0.87). By increasing the HDTMA-Br dosage, the ratios of turbidity/turbidity _initial and UV ₂₅₄ /UV _254-initial adsorbance by HA (after/before adsorption process) were decreased. In HDTMA-Br dosages of 7 and 10 g/l, the maximum removal efficiency for HA was 96 and 86%, respectively, with a slight variation in the pH value and turbidity unit. Conclusions: This study showed that modification of nanozeolite by cationic surfactants, to reduce its negative surface charge, could markedly improve its efficiency in the adsorption of disinfection by-product precursors from an aqueous solution. The HDTMA-Br/Clinoptilolite nanozeolite (CNZ) ratio of 0.07, pH have to coincide in iso-electric point, can be an optimum ratio for the modification.

Aims: The aim of this study is the recovery of municipal refuse and using it as a biosorbent for Nickel (II) and Chromium (VI) (Ni ^{2+ an} d Cr ⁶⁺ )removal from aqueous solutions. Materials and Methods: Activated sludge was obtained from the wastewater treatment plant in a dairy industry. All experiments were performed in the batch system and effective parameters such as the pH, adsorbent dosage, and the initial concentration and contact time of Ni ²⁺ and Cr ⁶⁺ were investigated. The adsorption isotherms and kinetics were evaluated to describe the metal uptake and dynamic reactions. Results: The results of this study showed that with an increasing adsorbent dose and contact time, Ni ²⁺ and Cr ⁶⁺ removal efficiency increased. The maximum adsorption of Ni ²⁺ and Cr ⁶⁺ was obtained in pH 6 and 2, respectively. Meanwhile, with increasing Ni ²⁺ and Cr ⁶⁺ concentration, the removal efficiency decreased. The results best fitted the Langmuir isotherm and the maximum absorption capacity of Ni ²⁺ and Cr ⁶⁺ onto dry activated sludge (DAS) were 2.17 and 2.23 mg/g, respectively. Analysis of the adsorption kinetics showed that the intraparticle diffusion kinetic had been good and presented Ni ²⁺ and Cr ⁶⁺ uptake onto DAS, and the intraparticle diffusion rate constant of Ni ²⁺ and Cr ⁶⁺ were 0.044 and 0.042 (mg/g min ^0.5 ), respectively. Conclusions: According to the results, dry activated sludge is suggested as a low cost and available adsorbent for removing Ni ²⁺ and Cr ⁶⁺ from aqueous solutions.

Aims: The aim of this study is to determine the PCE biodegradation potential in an Anaerobic Migrating Blanket Reactor (AMBR) that has not been used so far for the bioremediation of this compound, in high concentration, and to evaluate the system performance. Materials and Methods: This study was an Experimental - Interventional study that was done from April 2010 to March 2011, in the Isfahan University of Medical Sciences. The AMBR was used in a type of laboratory scale, with a volume of 10 L, which was divided into four compartments, for the biological degradation of PCE in a synthetic substrate. The startup was done using anaerobic digested sewage sludge. The performance of the reactor was evaluated during four periods, with a PCE loading rate of 3.75 until 75 mg PCE/L.d. The hydraulic retention time (HRT) was 32 hours. Results: Optimum chemical oxygen demand (COD) removal efficiency was obtained, 98%, with an organic loading rate (OLR) equal to 3.1 g COD/L.d. For PCE removal, the optimum efficiency was observed to be 99.8%, with a PCE loading rate equal to 37.5 mg PCE/L.d. The average COD and PCE removal rates for the whole activity period of the reactor were 91.4 and 99.5%, respectively; 1.1 ± 0.7% from the influent PCE was adsorbed on the biomass and 20% was found in the headspace. Conclusions: The AMBR reactor, which provides full-scale studies and uses real industrial wastewater polluted with PCE, is a simple, efficient, and reliable method for the treatment of PCE.