Avicenna Journal of Environmental Health Engineering

Research Article

24/12/2014

Effect of Chitosan as a Coagulant Aid Combined With Poly Aluminum Chloride Removing of Turbidity From Drinking Water

Abdolmotaleb Seid Mohammadi, Azam Mobarakian, Fatemeh Taherkhani, Ghorban Asgari

Chitosan, a biodegradable polymer, is used as an eco-friendly coagulant in a wide variety of applications in water and wastewater treatment. The present study aimed to investigate the effect of chitosan as a coagulant aid combined with poly aluminum chloride (PAC) to enhance coagulating efficiency for bentonite suspensions. A conventional jar test apparatus was used for the tests. The effect of various operational parameters, such as initial pH of the solution (5-9.5), dosage of chitosan (0.5-3.5 mg/L), dosage of PAC (5-35 mg/L) and initial turbidity (50-200 NTU) were investigated. The maximum turbidity removal rates were obtained as pH 8.5 for PAC and pH 7.5 for combined PAC and chitosan (CPC). The coagulating efficiency of bentonite using PAC and CPA was found to decrease with an increase in the pH value of the solutions. The maximum turbidity removal rate was achieved in coagulating by PAC (30 mg/L) alone, and PAC (20 mg/L) combined with chitosan (2.5 mg/L) as coagulant aid with the removal rate of 87% and 96%, respectively. The optimum dosage of chitosan required to obtain the highest removal rate was 2.5 mg/L. Hence, using chitosan as a coagulant aid can not only reduce the required amount of coagulant (35%) but can also enhance the removal turbidity efficiency.

Research Article

10/12/2014

Removal of Furfural From Wastewater Using Integrated Catalytic Ozonation and Biological Approaches

Mostafa Leili, Gholamreza Moussavi, Kazem Naddafi

Furfural with a chemical formula of C₅H₄O₂ is a toxic compound which has several health problems for both humans and environment. It has a few exposure routes for entering the human body such as oral, dermal or nasal. In the present study, the efﬁcacies of an integrated catalytic ozonation process (COP) and novel cyclic biological reactor (CBR) were explored for the removal of furfural from aqueous solutions. Activated carbon was purchased from Merck Company. It had a Brunauer, Emmett, and Teller (BET) specific surface area of 1100 m²/g, with an average micropore volume and size of 0.385 cm³/g and 595 µm, respectively. The results indicated that 30% pretreatment with COP could increase furfural and chemical oxygen demand (COD) removal efficiency with CBR 5.56% and 27.01%, respectively. With 70% pretreatment by COP, 98.57% furfural and 95.34% COD removal efficiencies happen in CBR. Generally, batch and continuous experiments showed that the integrated COP/CBR could be efﬁcient in eliminating furfural from wastewater and thus may be a promising technique for treating furfural-containing wastewater.

Research Article

24/12/2014

Natural Arsenic Pollution and Hydrochemistry of Drinking Water of an Urban Part of Iran

Mohammad Mosaferi, Mohammad Shakerkhatibi, Saeid Dastgiri, Mohammad Asghari Jafar-abadi, Alireza Khataee, Samira Sheykholeslami

Natural contamination of surface and groundwater resources with arsenic is a worldwide problem. The present study aimed to investigate and report on the quality of drinking water resources with special focus on arsenic presence in an urban part of Iran. Arsenic concentrations were measured by graphite furnace atomic absorption spectroscopy (GFAAS). In both surface and groundwater samples, arsenic concentrations ranged from 6 - 61 µg/L with an average value of 39 ± 20 µg/L. Concentration of arsenic, which was up to six times greater than guideline values (10 µg/L) indicates the presence of arsenic bearing materials in the geological structure of the region. It was found that the quality of treated surface water produced by the water treatment facility was good in respect to arsenic (9 µg/L) and solid content (EC = µs/cm). However, in drinking water samples of wells, total solids (mean EC = 1580 ± 150 µs/cm), total hardness (mean = 479 + 94 mg/L as CaCO3) and arsenic (mean = 42 + 16 µg/L) were significantly higher. Correspondingly, there was a significant correlation between arsenic concentration and EC, Na+, K⁺ and Cl^- values. The type of water in most of groundwater samples (70%) was determined as HCO^3-Na⁺. Considering the population of the city and probable health effects due to exposure to arsenic through drinking water, comprehensive measures as well as application of arsenic removal processes in water treatment facilities and replacement of contaminated wells with safe wells are required.

Research Article

24/12/2014

Photo Catalytic Removal of Sodium Dodecyl Sulfate From Aquatic Solutions With Prepared ZnO Nanocrystals and UV Irradiation

Mohammad Taghi Samadi, Mir Saeid Sayed Dorraji, Zolykha Atashi, Ali Reza Rahmani

In this study, ZnO Nano catalyst has been synthesized and examined as photo catalyst for UV-induced removal of Sodium Dodecyl Sulfate (SDS) from aquatic solutions. This anionic surfactant was selected based upon its toxicity, wide use in industrial laundry and as a primary pollutant in municipal waste water systems.This study aimed to investigate removal of surfactant, SDS, in a batch photo catalytic reactor under various operating conditions including ZnO suspension concentration, initial surfactant concentration and initial pH of solution to find out the desired condition for removal of surfactant. ZnO Nano crystals were synthesized using the precipitation method and ZnSO₄.7H₂O was used as the starting material and NaOH as precipitant. The removal of SDS reactions by UV/ZnO process was performed into a batch photo reactor. In addition, various operating conditions including ZnO suspension concentration, initial surfactant concentration and initial pH of solution were investigated. In total, 98% of surfactant was removed at 40 minute and removal efficiency of SDS increased with increasing pH up to nine and after that with increase in pH, efficiency decreased. Possible roles of inorganic oxidant on the reaction were discussed. The removal of SDS follows pseudo-first order kinetics. Based on the results of this study, ZnO-UV photo catalytic process can be used as an efficient method for further study in detergents removal.

Research Article

24/12/2014

Catalytic Potential of Nano-Magnesium Oxide on Degradation of Humic Acids From Aquatic Solutions

Ghorban Asgari, Javad Faradmal, Hassan Zolghadr Nasab, Abdolmotaleb Seidmohammadi

Catalytic ozonation is a new and promising process used to remove the contaminants from drinking water and wastewater. This study aimed to evaluate the catalytic potential of nano-magnesium oxide (nano-MgO) for the removal of humic acids (HA) from water. Mg (NO₃)₂ solution was used to prepare MgO powder by the calcination method. In a semi-batch reactor, the catalytic ozonation was carried out. The effects of the various operating parameters, including pH, reaction time, T-butyl alcohol (TBA) and phosphate on HA degradation were evaluated. Experimental results indicated that degradation of HA was increased as the pH solution and reaction time were increased. Maximum HA degradation was obtained at pH = 10 and the reaction time of 10 minutes in the catalytic process. The calculated catalytic potential of nano-MgO on ozonation of HA was 60%. Moreover, catalytic ozonation process was not affected by TBA and the main reaction on HA degradation HA have effect take place on MgO surface. According to the results of this study, the developed MgO catalyst is the active and proficient catalyst in HA degradation using the catalytic ozonation process.

Research Article

24/12/2014

Monopolar Electro-Coagulation Process for Azo Dye C.I. Acid Red 18 Removal from Aqueous Solutions

Ghasem Azarian, Davood Nematollahi, Ali Reza Rahmani, Kazem Godini, Mohammad Bazdar, Hassan Zolghadrnasab

The discharge of wastewaters containing an untreated dye results in aesthetic problems and an increase in gases solubility, which causes light transmission inhibition into water bodies. In spite of advantages of physicochemical and biological methods, these processes produce huge amounts of sludge, toxic by-products and require several oxidant chemicals. By contrast, electrochemical processes because of their high versatility, high efficiency and eco-friendly properties are more acceptable. In the present study, the removal of azo dye Acid Red 18 and chemical oxygen demand (COD) from synthetic wastewater by monopolar (EC) process was investigated and key parameters such as operating time, current density (CD), initial pH and energy, and electrode consumption were optimized. It was found that the process had a very good efficiency in the removal of both COD and color; for the iron electrode, the maximum amounts of color and COD removal were 99.5% and 59.0%, respectively. An operating time of 45 min, pH of 7 and CD of 1.2 mA/cm² was selected as the optimized condition. The optimization of variables is extremely crucial as it results in a decrease in costs, energy and electrode consumption. Overall, the iron electrode used less energy than the aluminum electrode and was more acceptable for use in this process due to economical reasons. The findings of UV/vis spectra illustrated that the structures of this dye were removed by the process. In comparison with traditional methods such as aerobic and anaerobic systems, the EC process is a suitable alternative for the treatment of wastewaters containing dye pollutants.

Research Article

24/12/2014

Assessing the Safety and Health Standards in Diagnostic Radiology Centers in Hamadan Province

Mohammad Reza Samarghandi, Kazem Godini, Hossein Ali Norouzi

Providing safety and health criteria is a very important part of the management of all diagnostic radiography centers. The prime aim of this study was to assess the safety and health standards of diagnostic radiology centers in Hamadan Province. This descriptive study that was performed in 22 imaging institutes, 21 hospitals, 1 faculty and 8healthcare centers (governmental and non-governmental) in Hamadan Province, Iran were selected. All of the X-ray radiography units (including the CT. Scan, panorex, mammography, simple radiography and portable X-Ray units) were evaluated in terms of physical status, radiation protection principals, health criteria and current condition according to the national performed standards of Ministry of Health and Atomic Energy Organization checklists. The findings showed that 106 x-ray units activated in 52 medical imaging centers in this city covering about 1.9 million people. Among 106 x-ray units, 49 were located in hospital wards and 57 were located in the other institutes in 9 townships. 36% of darkrooms, 68% of radiation rooms and 66% of control rooms were suitable in terms of physical status. 57% of health criteria factors had standard condition. Regarding to radiation protection term, the situation was unfavorable in comparison with physical status and health criteria, especially in the application of portable X-ray devices in the various wards of the hospitals. Radiology wards in Hamadan Province had obvious problems in the radiation protection principals; they need better management and maintenance to achieve the standards conditions in terms of safety and health.

Avicenna Journal of Environmental Health Engineering: Dec 2014, 1 (1), 7 articles.