فهرست مطالب

Avicenna Journal of Environmental Health Engineering - Volume:4 Issue: 2, Dec 2017

Avicenna Journal of Environmental Health Engineering
Volume:4 Issue: 2, Dec 2017

  • تاریخ انتشار: 1396/10/30
  • تعداد عناوین: 8
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  • Ashraf Mazaheri Tehrani , Rouhullah Dehghani , Hamid Reza Soheil Arezoomand , Hamid Reza Gilaasi , Zahra Tavakoli * Pages 1-5
    Formaldehyde is used in many industries for its different chemical characteristics. The wastewater in these industries contains large amounts of formaldehyde which is dangerous and toxic for human and environment. The purpose of this study was to investigate the efficiency of Fe2+/H2 O2 /O3 process in degradation of formaldehyde from synthetic wastewater. This experimental bench-scale study in batch system was conducted on the synthetic wastewater in primary concentration of formaldehyde (500 mg/L). The maximum percentage of formaldehyde removal was 72.5% that was observed in molar ratio of 2.4 [H2 O2 ]/[Fe2+]. After determining optimum [H2O2]/[Fe2+], the effects of pH variables, function time, and ozone concentration were studied in formaldehyde removal. In this process, the maximum degradation efficiency of formaldehyde in 0.7 mg/L ozone concentration and in 2.4 of molar ratio for [H2 O2 ]/[Fe2+] was 85.84% after 20 minutes. Moreover, the effect of pH and ozone concentration was significant in degradation efficiency (P<0.05). Generally, the Fe2+/ H2 O2 /O3 process seems to be a practical and reliable method in treating the industrial wastewater contaminated with high concentrations of formaldehyde.
    Keywords: Formaldehyde, Hydrogen Peroxide, Ferrous Sulfate, Ozone, Industrial Wastewater
  • Ali Arezoumand , Hamzeh Ali Jamali *, Hamid Karyab , Reza Ghanbari , Saeed Omidi Pages 6-12
    Malodors are one of the problems of water and wastewater treatment plants, especially in the vicinity of residential areas. Mineral compounds like hydrogen sulfide (H2S) and ammonia (NH3) produce unpleasant smells in the wastewater treatment plants. These gases also have adverse effects on both humans and the environment. After field visits around the plant, a number of 12 sampling stations were determined. Sampling stations were selected from 4 cardinal directions with regard to permanent trade winds and on distances of 0, 2 and 4 km from the plant. Sampling was performed in the morning and evening during the four seasons. Jacob and Indophenol methods were used for measuring the concentration of H2S and NH3.
    According to analysis of variance (ANOVA) and Tukey test, and concentrations of NH3 and H2S during different seasons, the emissions were more significant in the warm seasons and caused more malodors (P = 0.011, P = 0.004 for NH3 and H2S, respectively). Moreover, there was a significant relationship between the concentration of NH3 and sampling sites (P = 0.000). However, the relationship between the concentration of H2S and sampling stations was not significant (P = 0.179).According to the results, the concentrations of H2S and NH3 in all the seasons except for winter were within the threshold limits. The concentration of H2S in the summer and the concentration of NH3 in all the seasons were higher than USEPA standards and World Health Organization (WHO) guidelines.
    Keywords: Wastewater treatment plant, Malodor, Hydrogen sulfide, Ammonia
  • Reza Darvishi Cheshmeh Soltani , Mahdi Safari *, Reza Rezaee, Afshin Maleki, Omid Giahi , Reza Ghanbari Pages 13-18
    Humic substances are considered as one of the major natural organic contaminants in water resources. Presence of such substances in the drinking water supply resources results in poor water quality and jeopardizes the consumer’s health. In the present study, sonocatalytic decomposition of the humic substances by using MgO nanoparticles was investigated under the radiation of the ultrasonic waves. Accordingly, the X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques were used to determine characteristics of the nanoparticles. Furthermore, the effects of various parameters, including the amount of nanoparticles, initial pH, initial concentration of humic substances, contact time, as well as the power and frequency of ultrasonic waves on the efficiency of the sonocatalytic decomposition of humic substances were investigated. Results of the present study showed that the efficiency of sonocatalytic decomposition of humic substances was reduced by increasing the initial pH and initial concentration of the humic substances; while, the increased amount of the nanocatalyst resulted in the increased efficiency of decomposition. Furthermore, the obtained results indicated that the MgO sonocatalytic process could decompose the humic substances with the efficiency of 78.5% under optimal conditions (pH:7, initial concentration of humic substances: 20 mg/L, concentration of nanoparticles:1 g/L, power: 100%, frequency: 37 kHz and contact time:120 min). Based on the obtained results, the sonocatalytic method using MgO can remove humic substances and other similar organic matters from the aquatic environments with a high efficiency.
    Keywords: MgO nanoparticles, Humic substances, Sonocatalyst, Ultrasonic
  • Reza Shokoohi , Halime Almasi , Meysam Sedighi , Zahra Daraee , Somaye Akbari * Pages 19-23
    The presence of pharmaceutical wastewater containing antibiotic compound is one of the new problems relating to the environmental pollution. Antibiotic ciprofloxacin (CIP), widely used in medical treatments, can induce antibiotic resistance in low concentrations in the ecosystem and aqueous solutions. In this study, CIP was removed using moving bed biofilm reactor (MBBR) from real hospital-derived wastewater. This study was carried out at Beasat hospital in Hamadan, Iran. CIP (100 mL) was applied in 2 sets of plexiglass tubular columns as MBBR. Microorganisms were grown on the suspended carriers. To achieve this purpose, polyethylene kaldnes (K1) was chosen as reactor bed in 500 m2 /m3 specific area. The effect of operating parameters such as mixed liquor suspended solid (MLSS) (100, 1000, 3000 mg/L), hydraulic retention time (HRT) (8, 12, 24 hours), and support media with carrier K1 (30%, 50%, 70%) were evaluated. According to the results, the yield of CIP removal at 30%, 50%, and 70% of K1, reaction of 24 hours at MLSS 3000 mg/L was obtained 50.5%, 68.9%, and 97.6% respectively. In the same conditions, chemical oxygen demand (COD) removal was achieved 26.78%, 30.49%, and 80.07%, respectively. Results indicated that the MBBR process can be used as an effective approach for removing CIP and COD from hospital effluent. Moreover, these data suggested that the K1 carrier could be useful in terms of mineralization and efficiency. Furthermore, development of biofilm in MBBR was mostly affected by K1.
    Keywords: Ciprofloxacin, Antibiotic, Biological process
  • Shahla Shafiei , Mohammad Khazaei , Ramin Nabizadeh , Mohammad Fahiminia *, Mostafa Leili , Vahid Razmju , Reza Ansari , Mina Aghaei Pages 24-28
    This work aimed to apply the water safety plan (WSP), a plan suggested by the World Health Organization (WHO), to evaluate desalinated water supply system in Qom province of Iran, assisting a systematic prevention approach based on risk assessment. Major portion of Qom drinking water is supplied by an integrated membrane-based desalination system through a private water network. WSP includes 12 phases comprising chapters like "System Description", "Hazard Identification", and "Risk Assessment". The abovementioned phases were conducted according to filled checklists which finally served as the input data for WSP software, namely WSP QA Tool. The processed information by the software attributed to each step was presented finally as appropriate tables and histograms. Total score obtained for Qom desalinated water supply system via WSP was 302 whereas, the full obtainable score considered in WSP was 440. Accordingly, 68.6% of the total WSP obtainable scores was acquired. The scores achieved in steps "catchment", "treatment", "distribution", and "point of use" were 67%, 67%, 64%, and 65%, respectively. The minimum obtained score was 25% assigned to the step "Improvement Plan". The maximum scores were 100% and 97% attributed to "Identification of Stakeholders" and "Hazard Identification and Risk Assessment", respectively. The score of 68.6% from WSP was achieved by Qom desalinated water supply system. The step "Improvement Plan" should be performed simultaneously with the entire WSP to improve the coordination for better enforcement of the plan. To enhance the current condition, the funding demands assigned to each uncontrolled risk which is attributed to each improvement program must be supplied, ranked, and enforced.
    Keywords: Water safety plan, Water distribution network, Risk management, Drinking water, Qom
  • Mohammad Taghi Samadi, Ghorban Asgari, Ali Reza Rahmani, Zhila Ghavami * Pages 29-34
    In this experimental study, the performance of a fixed bed column containing a mixture of iron and aluminum modified with acid, as a reaction bed, was evaluated for the removal of heavy metals of cadmium, nickel, and copper. The tests were carried out by feeding the columns with aqueous solutions at the concentration of 100 mg/L using four iron/aluminum granular mixtures at various volume ratios (100/0, 50/50, 75/25, 25/75 and 0/100), and pH (3, 5, 7) for a total of 28 column tests. Results showed that metal ion removal was mainly accomplished via redox reactions that initiated the precipitation of mineral phases. At pH 5 and flow rate of 1 mL/min, the removal efficiency of cadmium, nickel, and copper at the 50/50 ratio of modified iron and aluminum was obtained higher than 99% and this removal efficiency could be kept about 50 hours. It seems that the column with the volume ratio of 75/25 of iron and aluminum mixture was the most efficient column for removing the heavy metals with the most suitable iron content and also high hydraulic performance due to the suitable aluminum content. It is therefore seen that the mixture of iron and aluminum can be used as an environmentally and economically viable remediation technology for the subsequent prevention of groundwater contamination.
    Keywords: Acid-washed iron-aluminum mixture, Copper, Nickel, Cadmium
  • Masoud Keikha * Pages 35-37
    Non-tuberculosis mycobacteria (NTM) are saprophytic bacteria in environmental resources such as water and soil. The presence of atypical mycobacteria in hospital resources may lead to infections and the spread of aerosol particles through ventilation systems, wind, and even drinking water. Therefore, control of contamination of environmental resources in hospitals is one of the most important approaches to reduce and manage NTM nosocomial infections. This study reported the isolation of Mycobacterium frederiksbergense from a tap water sample, which is considered important for clinical and biodegradation aspects. The isolated bacterium was identified using phenotypic features and 16S rRNA sequencing. This report verified the necessity to identify the presence of NTM in water and to find a solution for controlling such contaminations.
    Keywords: Mycobacterium frederiksbergense, 16S rRNA sequencing, Biodegradation, Infection
  • Masoud Keikha * Pages 38-39