Mohammad Ansarizadeh; Tayebeh Tabatabaei; Mohammad Reza Samaei; Mostafa Leili; Mohammad Mehdi Baneshi
Abstract
Background: Discharging antibiotics into the environment could cause great concern for scientists. In the present study, tetracycline (TC) antibiotic was photodegraded with titanium dioxide (TiO2) and zinc oxide (ZnO) fixed on the polyurethane (PU) in the presence of ultraviolet (UV) irradiation and ...
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Background: Discharging antibiotics into the environment could cause great concern for scientists. In the present study, tetracycline (TC) antibiotic was photodegraded with titanium dioxide (TiO2) and zinc oxide (ZnO) fixed on the polyurethane (PU) in the presence of ultraviolet (UV) irradiation and optimized through response surface methodology (RSM).
Methods: This experimental study was conducted on the most effective variables (pH, contact time, TC concentration, and catalyst doses) for experimental design. The experiments of degradation with the process of PU/UV/nanocatalyst composite were conducted with a reactor glass vessel (1000 mL) as batch mode.
Results: The results showed that the quadratic model can be used for the interpretation of experiments. The results of the model represented that all parameters had a significant effect on the tetracycline removal, and the degradation of antibiotics was obtained at the optimum condition that was 95% for ZnO/UV/PU and 97% for TiO2/UV/PU. The main radical for the degradation of TC was hydroxyl ions based on the scavenger study and the first-order kinetic model was best fitted with data. The highest removal efficiency was obtained at pH of 5.2, catalyst dose of 2.64g/m2, TC concentration of 25.21, reaction time of 82 min using ZnO/UV/PU and pH of 5.8, catalyst dose of 2.9 g/m2, TC concentration of 25.12, and reaction time of 90 min using TiO2/UV/PU.
Conclusion: It could be concluded that the process of nanocatalyst fixed on polyurethane can significantly eliminate the antibiotic in the presence of ultraviolet irradiation from the effluent of the wastewater treatment plant.
Mohammad Reza Samaei; Razieh Ashoori; Abooalfazl Azhdarpoor; Saeed Yousefinejad
Abstract
Background: Simultaneous existence of excessive amounts of fluoride and nitrate in drinking water can cause health problems for humans. In this study, simultaneous removal of fluoride and nitrate from aqueous solutions was investigated using a combination of electroreduction and electrocoagulation processes ...
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Background: Simultaneous existence of excessive amounts of fluoride and nitrate in drinking water can cause health problems for humans. In this study, simultaneous removal of fluoride and nitrate from aqueous solutions was investigated using a combination of electroreduction and electrocoagulation processes in a batch reactor with different electrodes. Methods: In this study, at first, an optimum electrode was selected. Afterward, the effects of different operating parameters such as the current density (12- 36 mA/cm2), initial pH (5.5-8.5), NaCl concentration (0.5-1.5gr/L), and electrolysis time (15-120 min), ) on the removal of fluoride (initial concentration: 6 mg/L) and nitrate (initial concentration: 150 mg/) were evaluated, respectively. Results: The highest efficiency of the concurrent fluoride and nitrate removal with Al-Cu electrode and in optimal experimental conditions of the current density of 36 mA/cm2, pH of 7, NaCl concentration of 1gr/L, and electrolysis time of 90 minutes was obtained 87.04 and 89.70%, respectively. Conclusion: High catalytic activity of the copper cathode resulted in better performance than other cathodes in the simultaneous removal of fluoride and nitrate. Generally, it can be concluded that the electrochemical process can reduce the levels of fluoride and nitrate to the amounts below the WHO standard limits, 1.5 mg/L and 50 mg/L, respectively.
Mohammad Reza Samaei; Majid Nozari; Marziyeh Ansari Shiri; Mehdi Mokhtari; Asghar Ghasemi; Reza Rezaei Javanmardi
Volume 5, Issue 2 , April 2017, , Pages 44-50
Abstract
Background:Discharge of raw or treated wastewater containing linear alkyl benzene sulfonate (LAS) into the environment causes significant public health and environmental problems. The purpose of this study was the treatment of hospital wastewater using an intermittent cycle extended aeration system (ICEAS).Methods:Experiments ...
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Background:Discharge of raw or treated wastewater containing linear alkyl benzene sulfonate (LAS) into the environment causes significant public health and environmental problems. The purpose of this study was the treatment of hospital wastewater using an intermittent cycle extended aeration system (ICEAS).Methods:Experiments were carried out on Yazd Shohaday-e-Kargar hospital wastewater treatment system and samples were collected in a 2 month period from the influent and effluent of the system. The used pilot study carried out consisted of two zones: pre-react and main react zones. They were divided using a baffle wall. Firstly, wastewater enters a pre-react zone and then through the opening at the bottom of the baffle wall it enters the main react zone. The cycle time and flow rate for the system were considered 6 h and 2 L/h, respectively. Then, the necessary tests were performed on the system’s influent and effluent.Results:The removal of BOD5, COD, and LAS by ICEAS were 94.54%, 92.97%, and 84.99%, respectively. The averages of SVI, F/M, MLSS and MLVSS in the system were 113 mL/g, 0.086 Kg.BOD5/Kg.MLSS.d, 4327 mg/L and 3172 mg/L, respectively.Conclusions:This work showed the excellent efficiency of ICEAS to effectively remove BOD5, COD, and LAS from hospital wastewater. The results of this research can help to manage wastewater treatment in hospitals.
Marziyeh Ansari Shiri; mansooreh dehghani; Mohammad Reza Samaei
Volume 4, Issue 3 , July 2016, , Pages 121-128
Abstract
Background: Atrazine is a widely used herbicide. The increasing salinity of many water resources has had a negative effect on atrazine biodegradation. The aim of this study was to isolate atrazine degrading bacteria in semi-salinity media. Methods: Nine selected bacterial species were cultivated on ...
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Background: Atrazine is a widely used herbicide. The increasing salinity of many water resources has had a negative effect on atrazine biodegradation. The aim of this study was to isolate atrazine degrading bacteria in semi-salinity media. Methods: Nine selected bacterial species were cultivated on the mineral salt broth culture medium containing atrazine (50, 100, 500 mg/L), NaCl concentration (10 g/L), and 2% (wt/vol) agar. The bacteria with higher growths in the atrazine medium (500 mg/L) were selected. Then, those with higher growths were transferred to the medium with atrazine concentration of 1000 mg/L. The atrazine biodegradation rates by Ochrobactrum oryzae and consortium bacteria (all of the nine bacteria species) were compared by cultivating separately on the mineral salt broth containing atrazine concentration of 30 mg/l, and NaCl concentration of 10 g/L in the incubation time of 10 day and HPLC analysis. Results: The results indicated that Ochrobactrum oryzae had the highest growth compared to the other investigated bacteria (Acinetobacter radioresistens, Paenibacillus lautus, and Bacillus sp) in the mineral salt broth culture medium containing atrazine concentrations (1000 mg/L), NaCl (10 g/L), and 2% (wt/vol) agar. In the Ochrobactrum oryzae and bacterial consortium comparison, atrazine biodegradation rate in the culture medium containing NaCl, by Ochrobactrum oryzae, was higher than bacterial consortium and atrazine biodegradation rate in the culture medium with no NaCl addition, by Ochrobactrum oryzae, was lower than bacterial consortium. Conclusion: Based on the results, Ochrobactrum oryzae was significantly capable of atrazine biodegradation in the semisalinity aqueous environment.
Mohammad Reza Samaei; Mohammad hasan Ehrampoush; Hoshang Maleknia; Zahra Elhamiyan; Ebrahim Shahsavani; Asghar Ebrahimi
Volume 4, Issue 2 , April 2016, , Pages 83-88
Abstract
Background: Heavy metals have destructive and irreversible effects on the human, plants and animals. Some industries in Yazd enter industrial wastewater to municipal wastewater collection system. This can lead to high levels of heavy metals in wastewater and in turn in the wastewater treatment plant ...
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Background: Heavy metals have destructive and irreversible effects on the human, plants and animals. Some industries in Yazd enter industrial wastewater to municipal wastewater collection system. This can lead to high levels of heavy metals in wastewater and in turn in the wastewater treatment plant effluent. Methods: This study was carried out during four months from December 22, 2009 to May 20, 2010. The experiment was performed on the inflow, outlet of anaerobic pond and first and second facultative ponds of wastewater treatment plant and then transferred to the laboratory and measured by atomic absorption spectroscopy. Results: The results of the experiments showed that the average cadmium concentrations in the inflow, anaerobic pond outlet, and first and second facultative pond outlet were 0.0066, 0.0087, 0.0076, and 0.0083μg/l, respectively. The average amounts of chromium in the inflow, anaerobic pond outlet, and first and second facultative pond outlet were 0.0076, 0.0065, 0.0043, and 0.0056 μg/l, respectively. Cadmium concentration in the effluent was higher than standard. Conclusion: The comparison of the obtained data with Iranian standards for wastewater treatment for reuse in irrigation shows that the cadmium concentration exceeded the standard and the chromium concentration was lower than the standard. Therefore, it is not suitable for reuse in the crop farms and aquatic life.
Fahime Khademi; Mohammad Reza Samaei; Kourosh Azizi; Abbas Shahsavani; Hassan Hashemi; Aida Iraji; Abdolkhalegh Miri
Volume 4, Issue 1 , January 2016, , Pages 2-6
Abstract
AbstractBackground: Biogas is obtained by anaerobic decomposition of organic wastes buried materials used to produce electricity, heat and biofuels. Biogas is at the second place for power generation after hydropower and in 2000 about 6% of the world power generation was allocated to biogas. Biogas is ...
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AbstractBackground: Biogas is obtained by anaerobic decomposition of organic wastes buried materials used to produce electricity, heat and biofuels. Biogas is at the second place for power generation after hydropower and in 2000 about 6% of the world power generation was allocated to biogas. Biogas is composed of 40–45 vol% CO2, 55–65 vol% CH4, and about 1% non-methaneVOCs, and non-methane volatile organic compounds. Emission rates are used to evaluate the compliance with landfill gas emission regulations by the United States Environmental Protection Agency (USEPA). BTEX comounds affect the air quality and may be harmful to human health. Benzene, toluene, ethylbenzene and xylene isomers that are generally called BTEX compounds are the most abundant VOCs in biogas.Methods: Sampling of VOCs in biogas vents was operated passively or with Tedlar bags. 20 samples were collected from 40 wells of old and new biogas sites of Shiraz’ landfill. Immediately after sampling, the samples were transferred to the laboratory. Analysis of the samples was performed with GC-MS.Results: The results showed that in the collection of the old and new biogas sites, the highest concentration of VOCs was observed in toluene (0.85ppm) followed by benzene (0.81ppm), ethylbenzene (0.13ppm) and xylene (0.08ppm).Conclusion: The results of the study showed that in all samples, most available compounds in biogas vents were aromatic hydrocarbon compounds.These compounds’ constituents originate from household hazardous waste materials deposited in the landfill or from biological/chemical decomposition processes within the landfill.
Abooalfazl Azhdarpoor; Roya Nikmanesh; Mohammad Reza Samaei
Volume 3, Issue 2 , April 2015, , Pages 56-63
Abstract
Background: Contamination of water with arsenic has attracted the researchers’ attention as a global problem in recent years and has been observed in some parts of Iran. The purpose of this study is to assess the efficiency of welding iron waste in removing arsenic from aqueous solutions. Methods: ...
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Background: Contamination of water with arsenic has attracted the researchers’ attention as a global problem in recent years and has been observed in some parts of Iran. The purpose of this study is to assess the efficiency of welding iron waste in removing arsenic from aqueous solutions. Methods: In this study, the effects of different parameters, such as pH (3-9), initial concentration of arsenic (100-3000 μg/l), contact time (5-90min) and adsorbent dose (2.5-20 g/l), were studied. The final concentrations of arsenic were analyzed by atomic absorption. Results: The results indicated that at pH=3 and fixed dose of 1 g, arsenic removal efficiency of iron waste was 89.73%. By increasing the pH to 7, the removal efficiency increased to 96.44%. Also, an increase in the amount of iron waste from 2.5 to 10g/l, the removal rate increased from about 42.37% to 96.70%. For contact times of 5 and 30 minutes, the removal rate was 9% and 96.62%, respectively. Then, with increasing the contact time to 90 minutes, the removal rate increased to 99.24%. Correlation coefficient of Freundlich and Langmuir isotherms for As(III) was 0.7593 and 0.9979, respectively . Conclusion: The results of the study showed that welding iron waste has a high potential as an effective, fast and cheap method for removal of arsenate and arsenite from aqueous solutions.
majid nozari; Mohammad Reza Samaei; Mansooreh Dehghani
Volume 2, Issue 3 , July 2014, , Pages 113-124
Abstract
Background: Among Alkanes, N-Alkanes with medium chain have been identified as the most important contaminants of the soil. N-hexadecane (C16H34) with low solubility in water also belongs to this group and has been used by many researchers as a model contaminant. The present study aimed to investigate ...
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Background: Among Alkanes, N-Alkanes with medium chain have been identified as the most important contaminants of the soil. N-hexadecane (C16H34) with low solubility in water also belongs to this group and has been used by many researchers as a model contaminant. The present study aimed to investigate the effect of the external source of carbon (glucose) as co-substrate on removal of hexadecane from the soil.Methods: In this study, a Slurry Sequencing Batch Reactor (SSBR) was used as a pilot by a bacterial consortium, including bacterium Acinetobacter radioresistens, Bacillus subtilis, and Pseudomonas aeruginosa, in order to remove different concentrations of hexadecane (1,4,7, and 10 percent).Sampling was performed four times during the sedimentation step. Then, the samples were analyzed by GC-FID and the results were analyzed statistically.Results: The results showed that hexadecane removal (%) by the microbial consortium was higher in lower initial concentrations in such a way that the biological removal of hexadecane was respectively 45.95%, 38.55%, 34.39%, and 32.40% in the concentrations of 1%, 4%, 7%, and 10% on the third day. Moreover, adding the external carbon source (glucose) on the first day caused a 16% increase in hexadecane removal, which is 1.4 times more than the amount of hexadecane removal in the conditions without co-metabolism.Conclusion: The results showed that SSBR could be used as an exit-situation effective method for hexadecane removal in low concentrations through considering the effective factors in its function, such as dissolved oxygen, pH, and temperature. Also, adding the secondary carbon source could be effective in hexadecane removal from the soil. Yet, this effect might vary on different days.
