Iranian Journal of

Background and Objective: Nitrate is one of the dissolved anions having great health importance in water. Human activities and natural sources are considered as the main roots of nitrate intrusion in to water bodies. The main objective of this paper was to study nitrate removal by packed bed column filled with (PAN)-oxime-nano Fe₂O₃. Materials and Methods: PAN-oxime-nano Fe₂O₃ were synthesized and used as an adsorbent in glass column for the removal of nitrate from aqueous solution. Nitrate solution tank was set above the prepared column. The effect of factors, such as flow rate (2, 5, and 7 mL/min) and bed depth (5, 10, and 15 cm) were studied. Results: It was found that the data fit well with Thomas model and breakthrough curve was designed accordingly. The column performed well at lowest flow rate. As the flow rates and time increased, earlier breakthrough was observed. The column breakthrough time (C_e/C₀ = 0.05) was reduced from 9 to 4 h, as the flow rates increased from2 to 7 mL/min. Conclusion: fixed-bed using PAN-oxime-nano Fe₂O₃ exhibited good removal of nitrate. The adsorption studies showed that at longer bed depth, better removal of nitrate would be achieved. Thomas model was suitable for the normal description of breakthrough curve at the experimental condition. The data also were in good agreement with logistic regression.

Objective and Background: Fluoride is an element widely found in the earth crust. Advantages and disadvantages of fluoride in the human body are depended on its concentration. Long-term consumption of drinking water contaminated with arsenic can cause adverse health effects such as skin lesions and cancer in humans. The aim of this study was to study efficiency of nano alumina on multi walled carbon nano tube  for removal As(V) and fluoride from aqueous solution.

Materials and Method: In this study, nano-scale crystalline alumina was synthesized on single walled carbon nanotube by sol-gel method for using as a sorbent for solid phase extraction of Fluorine ion and arsenic(V). Response surface methodology based on Box-Behnken was used to assess the effect of independent variables on the response function and prediction of the best response value. In this study, effect of different parameters, such as contact time (10 to 120 min), pH (3-9), adsorbent dosage (0.25-1.5 g/L) and initial concentration of fluoride (2-8 mg/L) on efficiency of process was investigated. The structure of nano-scale alumina on multi walled carbon nano tube was determined by XRD and SEM techniques. Moreover, Freundlich and Langmuir isotherm models were used to calculate equilibrium constant.

Results: It was found that by increasing contact time and adsorbent dosage the rate of fluoride removal increased. However, by increasing pH and initial concentration the efficiency of fluoride removal decreased. High value for R² (0.94) shows that removal of arsenic(V) can be described by this model. The Freundlich isotherm was the best fitted graph for experimental data with R² more than 0.997.

Conclusion: In this study, it was observed that efficiency of arsenic(V) and fluoride  removal was greatly increased by using nano-scale alumina on multi walled carbon nanotubes (MWCNTs).

Background and Objectives: Remaining of crude oil in storage tanks usually results in accumulating oily sludge at the bottom of the tank, which should be treated and disposed of in a suitable manner. The efficiency of in-vessel composting process in removing total petroleum hydrocarbons (TPH) from bottom sludge of crude oil storage tanks was investigated in the present study.

Material and methods: The sludge was mixed with immature compost at the ratios of 1:0 (as control), 1:2, 1:4, 1:6, 1:8, and 1:10 (as dry basis) with the initial C:N:P and moisture content of 100:5:1 and 55% respectively for a period of 10 weeks. The moisture adjustment and mixing process were done 3 times a day during the composting period. Sampling and analysis of TPH and pH were done every week and every two days, respectively.

Results: TPH removal in the 1:2, 1:4, 1:6, 1:8, and 1:10 composting reactors was 66.59, 73.19, 74.81, 80.20, and 79.91%, respectively. Thus, initial adjustment of sludge to immature compost ratios plays a great role in reduction of TPH. The results of the control reactors indicated that the main mechanism of TPH removal in the composting reactors was biological process.

Conclusions: In-vessel composting by addition of immature compost as amendment is a viable choice for bioremediation of the bottom sludge of crude oil storage tanks.

Background and Objective: Arsenic is one of the most toxic pollutants in groundwater and surface water. Arsenic could have lots of adverse impacts on human health. Therefore, access to new technologies is required to achieve the arsenic standard.

Materials and Methods: The present study was conducted at laboratory scale in non-continuous batches. The adsorbent of zero-valent iron nanoparticles -Chitosan was produced through reducing ferric iron by sodium borohydride (NaBH₄) in the presence of chitosan as a stabilizer. At first, the effect of various parameters such as contact time (5-120 min), pH (3-10), adsorbent dose (0.3-3.5 g/L) and initial concentration of arsenate (2-10 mg/L) were investigated on process efficiency. Then optimum conditions in terms of contact time, pH, adsorbent dose and initial concentration of arsenate were determined by RSM method. Freundlich and Langmuir isotherm model equilibrium constant, pseudo-first and second order kinetic constants were calculated. The residual arsenate was measured y using ICP-AES.

Results: The optimum values based on RSM for pH, absorbent dose, contact time, and initial concentration of arsenate were 7.16, 3.04 g/L, 91.48 min, and 9.71 mg/L respectively. Langmuir isotherm with R²= 0.9904 for Arsenate was the best graph for the experimental data. According to Langmuir isotherm model, the maximum amount of arsenate adsorption was 135.14mg/g. . The investigation of arsenate adsorption kinetics showed that arsenate adsorption follows the pseudo-second kinetics model.

Conclusion: This research showed that the adsorption process is depended on pH. With increasing pH, the ability of amine groups in chitosan are decreased to protonation, caused to decrease the efficiency of arsenate removal at high pH.

Background and Objectives: Considering the complexity, cost, and time-consuming techniques of detecting Cryptosporidium oocysts and Giardia cysts,  B. subtilits spores have been introduced as microbial indicators of these pathogens to evaluate the efficacy of disinfection studies. The present study was aimed to investigate the feasibility of B. subtilis spores inactivation using hydrogen peroxide combined with copper and silver ions. A new glutaraldehyde based compound used for surface disinfection was also tested.

Materials and Methods: In order to sporulation, vegetative bacteria were allowed to grow on a medium with insufficient nutrients, and after 5 days incubation at 37˚C, spores were washed and purified. Spore suspension was used to prepare synthetic water. Disinfection efficiency was reported as logarithmic decrease of initial spore count.

Results: This research found that none of the disinfection compounds was able to spore inactivation in low initial concentration. The highest spore reduction efficiency was related to HP/Cu⁺² with 1.48 log inactivation, and HP/Ag⁺ compound placed in the second rank with 1.03 log reduction. Maximum spore reduction of 0.6 log was achieved when glutaraldehyde based disinfectant was used in disinfection process.

Conclusion: According to the results, it can be concluded that spores are very resistant even to combination of disinfectants. Spore reduction potential of the studied compounds was as follows: HP/Cu⁺²> HP/Ag⁺> glutaraldehyde based compound.

Background and Objective: In this study, WQI was estimated using an Iranian software called IWQIS to assess drinking water quality in Ray Township distribution systems.

Materials and Methods: The assessment of 73 samples of drinking water during 2013 and the comparison of 18 physicochemical parameters with the standard Code of 1053 (Iran National Standard) was done.

Results: The results showed that the concentration of 7 parameters is out of normal range in special percentage of the samples. Those parameters are as follow: total hardness (31.5%), Mg (46.6%), nitrate (50.68%), Na (45.2%), F (42.46%), Cl (2.7%), Sulfate (28.76%) of samples. The medium concentration of theses parameters was: total hardness (375 mg/L), Mg (32 mg/L), Nitrate (47.43 mg/L), Na (187 mg/L), F (0.5 mg/L), Cl (169 mg/L), and Sulfate (263 mg/L). It is estimated that 5.6% of the population of this township are highly exposed to nitrate, 79.1% to fluoride and 13.5% are exposed to sodium. The average WQI in Rey Township in a good spectrum is 71.22.

Conclusion: 17 samples (23.2%) were assessed in excellent spectrum, 54 samples (74%) in good and 1 sample (1.4%) in very poor spectrum and 1 sample in unsuitable condition were assessed. No sample was assessed in poor situation. The samples of the autumn showed the worst quality.

Background and objectives: Swimming is one of the most popular sport fields and entertainments that has considerable benefits for human health, but on the other hand microbial water contamination in swimming pools through transmission and spread of infectious diseases is a significant threat against public health. In this study, microbial water quality of all public swimming pools in Tehran were assessed and effective factors on microbial water quality were analyzed.

Materials and Methods: This cross-sectional study with the analytical approach was performed in 2013. The whole public swimming pools in Tehran were inspected and water samples were taken for measurement of microbial indicators including thermotolerant coliforms, heterotrophic plate count (HPC), and physicochemical parameters affecting the microbial water quality including turbidity, free residual chlorine and pH and an integrated swimming pool microbial water quality index were used to describe the overall situation. Operational parameters with probable effects on microbial water quality were checked through inspection using a checklist.

Results: The assessment of the swimming pool microbial water quality indicated that the compliance rates of thermotolerant coliforms and HPC were 91.4 and 84.5%, respectively. Compliance rates of free residual chlorine, turbidity, Ph, and temperature were also obtained to be 82.7, 45.5, 85.6, and 65.4% respectively. Based on the integrated swimming pool microbial water quality index, the proportions of swimming pools with excellent and good microbial water quality were 39.6 and 50.4% respectively and the others had not proper microbial water quality. The parameters of water free residual chlorine and turbidity, swimmer density, water recirculation period, dilution amount, cleaning, usage rates of shower and disinfection basin and operation of water treatment systems had significant effects on the microbial indicators (P<0.05).

Conclusion: The study showed that the overall microbial water quality status of public swimming pools in Tehran was acceptable and analysis of the results determined the most efficient interventions for improvement of the microbial water quality of the pools.

Background and Objective: Increasing air pollution and consequently adversely effects on the quality of life for many people has resulted in the use of the air quality indice for determination of the actual amount of pollutants and air quality, as one of the most important and effective measures for air quality control, to be considered further. The air quality health index (AQHI) is a new index related to air pollution developed in collaboration with Environment Canada and Health Canada, in 2001. The purpose of this study was to design and develop a software system for calculating AQHI for the first time in the country that calculates the health effects caused by the presence of several pollutants (NO_2, O_3,PM_10, and PM_2.5) at the same time with a new approach.

Materials and Methods: To achieve those aims, the software was designed and coded in Visual Basic. Net. After preparation of the software, it was tested using the real-time database of  six air pollution monitoring stations in Tehran including Aghdasyeh, Setad Bohran, Shahrdari 4, Golbarg, Park-e- Roz, and Shahrdari 11.

Results: This program is a software package installed on the computer with the possibility of exporting Excel file. The performance of software testing was verified using real data.

Conclusion: The results of the verification tests show that the index calculated by the software introduced and presented in this study can be used as a useful tool to assess air quality.

Background and Objective: The present study was carried out to determine the amount and ionic characterization of TSP and PM₁₀ aimed at identifying  the potential emission sources of particulates in the ambient air of Tabriz.

Materials and Methods: TSP and PM₁₀ samples were collected by two high volume samplers during September 2013 to August 2014. Water-soluble ions in particulate matter were extracted using ultrasonic method and were identified by ion chromatography. Using Stata12 software, linear regression analysis was performed between the ions to determination of the major ionic component of the particulates. In addition, in order to identify the potential emission sources of PM₁₀, the rotation varimax model was used.

Results: Total measured water-soluble ions in TSP and PM₁₀ of the urban sampling site were 20.33±20.77 and 16.04±14.08 µg/m³, respectively. Among all detected ions, sulfate (8.69±5.79 µg/m³) and nitrate (8.47±7.9 µg/m³) were the dominant constituents followed by calcium and sodium.

Conclusion: The modeling results revealed that the soils of surrounding ground together with secondary PM and also resuspension of PM from polluted soil account for 80 percent of PM₁₀ mass.

Background and Objective: The performance of in-vessel composting process, as one of the most effective methods of oily sludge treatment, depends on factors such as nutrients and temperature. Therefore, it is crucial to investigate the trend of changes of these factors. The aim of the present study was to investigate the trend of changes of organic carbon, nitrogen, phosphorus, and temperature during the composting of bottom sludge of crude oil storage tanks.

Materials and Methods: The sludge was mixed with the immature compost at the various ratios of sludge to compost including 1:2, 1:4, 1:6, 1:8, and 1:10 with the initial C/N/P of 100/5/1 and then was composted for a period of 10 weeks. The process of mixing and moisture adjustment of the mixtures was done 3 times a day during the composting period. Sampling and analysis were performed every week for organic carbon, nitrogen, and phosphorus and every day for temperature.

Results: The research indicated that the concentrations of organic carbon, nitrogen, and phosphorus were decreased sharply during the first weeks of the process and then they were decreased gently. At the final stage of the composting, the ratios of C/N and C/P increased from 20:1 and 100:1 to 26:1 and 166:1, respectively. In addition, the temperature of the reactors was kept in the mesophilic range during the process period.

Conclusion: The similar trend of decrease of organic carbon, nitrogen, and phosphorus in the composting reactors is an indication of decreasing the activity of the microorganisms involved in petroleum hydrocarbons degradation.  

Background and Objective: Water corrosion and scaling are known as destructive phenomenon of drinking water quality and water facilities. In this study, the groundwater tendency to corrosion or scaling in source water, water storage reservoirs and distribution system were studied. Simultaneous use of some qualitative and a quantitative index along with statistical analyses to assess the water scaling or corrosion tendency were investigated.

Materials and Methods: The data analysis of groundwater, water storage reservoirs and water distribution system in rural area of Kurdistan province were analyzed and the amount of Langelier (LI), Ryznar (RY), Pockorius (PSI) and Larson–Skold (LS) and CCPP indices were determined. Corrosion and scaling threshold for qualitative indices were determined based on CCPP index. The mean of indices was compared with the thresholds using independent t-test. ANOVA was used to assess the difference between the indices in different sources of water.

Results: The balance range for LI, RY and PSI found to be -0.1-0.05, 7-9 and 7.1-8.5. The mean CCPP for groundwater, reservoirs and networks were 9.27 ± 1.29, 9.13 ± 1.25, 11.25 ± 1.23, respectively. All three sources of water have some tendencies toward scaling; however, a significant balance status was confirmed statistically. According to Larson–Skold index, sulfate and chloride anions did not play a role in scaling process.

Conclusion: The use of qualitative indices with CCPP index can provide more accurate estimation of water tendency toward scaling or corrosion. The assessment of qualitative indices along with CCPP is recommended in drinking water corrosion monitoring studies.

Background and Objective: Polycyclic aromatic hydrocarbons (PAHs) are a group of organic pollutants that are mostly generated during the incomplete combustion. The main objective of this study was to characterize potential sources of PAHs in Tehran.

Materials and Methods:, Samples of PM₁₀ were collected at 10 monitoring stations belonging to Tehran Air Quality Control Company (AQCC) and transferred to laboratory for analysis. Besides, a SKC Flite 2 Air Sampling Pump (SKC, USA) equipped with a sampling head and PM₁₀ size-selective inlet was used at four stations to compare the results obtained by collecting AQCC monitors (AQCCMs) tapes with the standard sampling procedures for assessing the interchangeability of two field sampling methods. The principal component analysis (PCA) and diagnostic ratios were applied to identify emission sources and source contribution.

Results: The average diagnostic ratios of phenanthrene (Phe)/ (Phe+anthracene (Ant)), benzo(a)anthracene (BaA)/ (BaA+chrysene (Chry)), fluorantene(Flu)/ (Flu+pyrene (Py)), and indeno(1,2,3cd) pyrene (IcP)/(IcP+benzo(ghi)perylene (BghiP)) in samples were 0.79, 0.52, 0.43 and 0.38, respectively. These ratios showed that the combustion, especially fossil fuels and motor vehicles, was the main sources of PAHs emission in Tehran. The results of  PCA analysis also indicated that 49, 29 and 22% of PAHs sources in Tehran atmosphere were attributed to gasoline-driven vehicles, diesel vehicles and other sources, respectively.

Conclusion: According to the results, the combustion, especially fossil fuel and motor vehicle, was the main sources of PAHs emission in Tehran.

Background and Objective: Bottled water consumption is rapidly increasing in recent years for various reasons.The main aim of this study was to survey the geological origin of Iranian bottled water and determine compliance or lack of compliance with the experimental data obtained through sampling 71 brands of drinking bottled water and mineral water.

Materials and Methods: In this study the coordinates of access points as a georef of the chosen points were launched on the "Iran geological map" and "Iran mineral and warm water map." The compliance of laboratory data and water types with the geological data were evaluated and compared with the important ionic ratios of the extracted water through using awh software.

Results: In examining 71 brands of the bottled water, 28% of the brands did not agree with the laboratory results, reflected by observing higher levels of bicarbonate in 50% of the bottled waters than those of the geological data.. Additionally, 70% of water types were calcic bicarbonate. In the bottled waters from North Alborz range with coastal Time deposits around the Caspian Sea, there was a source of brine or sea water that was about 55% of this amount.

Conclusion: Water pass through different geological structures and the dissolution phenomenon might be an important factor for the observed disagreement. Because chemical treatment and use of additives on mineral waters are not allowed it prompts further studies to determine the cause and origin of this issue through sampling from the factory and water source.