A Seid-Mohammadi, Ar Rahmani, Gh Asgari, S Bajalan, A Shabanloo,
Volume 10, Issue 1 (6-2017)
Abstract
Background and Objective: Main sources of 4-chlorophenol wastewater are petroleum industry, coal, paper and resin production. The aim of this study was to compare the performance of raw and cationic surfactant modified nanoclay in removal of 4-chlorophenol from aqueous solutions.
Materials and Methods: The influence of contact time, initial pH of solution, adsorbent dosage and 4-chlorophenol concentration as effective parameters in adsorption process and the influence of modification solution pH and surfactant loading rates were investigated. The modified nanoclay was characterized by Fourier transform infrared (FTIR) and X-ray diffraction (XRD) spectroscopy. Finally, the isotherm and adsorption kinetics were investigated.
Results: The removal efficiency of 4-chlorophenol was increased by increasing the initial pH from 3 to 11, so that after of 120 min, the absorption efficiency at an initial 4-chlorophenol concentration of 100 mg/L and 0.25 g adsorbate was 26 and 95.5 % at pH 3 and 11, respectively. Under the same conditions the removal efficiency for the raw nanoclay was 2 and 9% at pH 3 and 11, respectively. The FTIR and XRD analyses revealed that the nanoclay structural changed from hydrophilic to hydrophobic and the interlayer spacing was increased. The adsorption of 4-chlorophenol on raw and modified nanoclay was consistent with Langmuir and pseudo-second-order kinetics. The maximum absorption capacity of raw and modified nanoclay was 0.5 and 25.77 mg/g, respectively
Conclusion: The modification of nanoclay with cationic surfactant increased the adsorption efficiency of 4-chlorophenol.
P Baratpour, G Moussavi, A Alahabadi, E Fathi, S Shekoohiyan,
Volume 10, Issue 2 (9-2017)
Abstract
Background and Objective: With industrial development and population growth, the emerging contaminants enter into the natural water resources. Therefore, adsorption potential of Ammonium Chloride-induced activated carbon (NAC) to remove metolachlor pesticide from contaminated water was investigated in this study.
Materials and Methods: The effects of operational conditions including solution pH, NAC concentration, metolachlor initial concentration and contact time on the removal of metolachlor by Ammonium Chloride-induced activated carbon (NAC) and standard activated carbon (SAC) were studied.
Results: Over 92.4% of 50 mg/L metolachlor was adsorbed using 0.3 g NAC/L within 5 min, and by increasing the reaction time to 60 min the removal efficiency reached to 100%. Under similar experimental conditions, standard activated carbon (SAC) could only adsorb 20% of metolachlor within 5 min and increase of contact time to 40 min caused the improvement of metolachlor adsorption onto SAC to 48%. The adsorption onto SAC was not influenced by the contact time over 40 min. Kinetic analysis showed that experimental adsorption data for both NAC and SAC were best fitted to the pseudo-second-order model. The maximum adsorption capacities of metolachlor onto NAC and SAC calculated by the Langmuir model were 344.8 and 238.1 mg/g, respectively.
Conclusion: Generally, these results showed that developed NAC was an efficient adsorbent with high removal efficiency for eliminating the halogenated pesticides from the contaminated water streams.
R Shokohi, A Shabanloo, F Zamani,
Volume 10, Issue 2 (9-2017)
Abstract
Background and Objective: Nitrophenols are among the most common and toxic compounds in industrial effluents that 2, 4 dinitrophenol (2, 4-DNP) is the most toxic compound in this group. The object of this study was to optimize the removal of 2, 4-DNP by thermally activated persulfate using a central composite design.
Materials and Methods: This study was performed on a batch thermal reactor with a volume of 4 L. In this study, a central composite design (CCD) with RSM method was used for designing and optimizing the operation parameters such as initial pH of solution, potassium persulfate concentration and temperature. The effect of 2, 4-DNP concentration and reaction time at optimum conditions were also investigated.
Results: The results indicated that the degradation rate of 2, 4-DNP was enhanced by increasing the concentration of persulfate and reducing temperature and pH. The optimum conditions for the highest degradation efficiency (99%) were as initial concentration 10 mg/L, reaction time 30 min, temperature 60 °C, Potassium persulfate concentration 10 mmol/L, and pH 5. At the optimum conditions, when 2, 4-DNP concentration was increased to 50 mg /L, the 2, 4-DNP degradation rate decreased to 73%.
Conclusion: This study indicated that the heat-activated PS oxidation could be an efficient approach for decomposition of 2, 4-DNP. Temperature was the most influential variable in this regard (p<0.0001).
M Kermani, M Farzadkia, A Esrafili, Y Dadban Shahamat, S Fallah Jokandan,
Volume 10, Issue 2 (9-2017)
Abstract
Background and Objective: Discharge of industrial wastewater containing Catechol has adverse effects on human and environmental health. Purpose of this study was to determine the effects of catechol toxicity before and after advanced oxidation process (ozonation process) by bioassay test with Daphnia Magna.
Materials and Methods: This study is an applied research in which the toxicity of catechol was determined by Daphnia Magna bioassay test during the ozonation process. First, Catechol stock solution was prepared at a concentration of 250 mg/L. Then, 10 samples were prepared that each contained 0 (control), 0.5, 1, 3, 6, 12, 25, 50, 75 and 100% of volume of primary solution. Initial samples were prepared from reactor effluent in the same volume as those of the samples. According to standard method, 10 Daphnia infants were added to each sample. The samples were observed after 24, 48, 72 and 96 hours. Finally, lethal concentration (LC50) and toxicity unit (TU) were calculated using Probit analysis.
Results: According to the results, Daphnia magna was affected by the toxicity of catechol. LC50 (24-hour) for raw effluent was increased from 13.30 mL/100 mL to 30.4 mL/100 mL after 60 minutes Treatment. The toxicity unit was decreased from 7.51 TU to 3.29 TU accordingly, showing reduction of 56% in toxicity. The toxicity of the treated effluent decreased during ozonation process of catechol.
Conclusion: Based on the bioassay test, ozonation process was able to reduce the toxicity of catechol. Therefore, this process can be used as an option to treat wastewater that contains catechol.
R Bagheri, S Sobhanardakani, B Lorestani,
Volume 10, Issue 3 (12-2017)
Abstract
Background and Objective: In countries such as Iran that are facing with water scarcity and water crisis, paying attention to the quantity, quality and sustainable use of water resources is very significant. Petrochemical processes discharge pollutants into the environment, contaminating surface water resources. Therefore, treatment of the wastewater of these industries is necessary. Due to the capabilities of AHP process such as generalization, consideration of various parameters, multi-dimensional selection and quantifying the qualitative parameters by experts, the current study was carried out to select the best wastewater treatment alternative for HDPE plant of petrochemical research and technology company-Arak center based on AHP in 2016.
Materials and Methods: In this study, both sequencing batch reactors (SBR) and extended aeration activated sludge (EAAS) systems based on environmental, technical-functional, economic and management criteria's according to the expert's opinion were weighted. Then, the paired comparisons of the selected wastewater treatment systems for each criterion were developed. Finally, the results were analyzed to select the best wastewater treatment systems for HDPE unit of petrochemical industries using Expert Choice 11 Software.
Results: The results showed that the SBR wastewater treatment system was the best method for the wastewater treatment of HDPE plant of petrochemical research and technology company-Arak center as compared with the ESSA system. Also, consistency ratio was ranged from 0 to 0.10 in all emphases. Based on the results of the sensitivity analysis, the SBR system had the highest priority of economic and environmental criteria. The ESSA system had the highest priority of technical-functional and management criteria.
Conclusion: Based on the results, although ESSA method requires more maintainance and management than the SBR method, due to increasing requirement for the compliance of the output effluent quality with permissible limits and the need for less land for the establishment of the treatment plant, the SBR method was selected to be the most suitable process for HDPE plant wastewater treatment.
H Kamani, Ah Panahi, Sd Ashrafi, F Kord Mostafapour, Ns Omrani Gargari,
Volume 10, Issue 3 (12-2017)
Abstract
Background and Objective: Extreme use of antibiotics and discharging to the environment lead to serious consequences. Mesoporous silica such as MCM-41 material is widely used to absorb contaminants from the aqueous solution. The aim of this study was to evaluate mesoporous synthesis of MCM-41 and its efficacy for removal of the antibiotic cephalexin from aqueous solution.
Materials and Methods: Physical characteristics and absorbent structure synthesized by techniques BET, FTIR and XRD were analyzed. The effect of variables such as pH values (3, 7, 11), the dose of MCM-41 (200, 500, 800 mg/L), initial concentration of cephalexin (50, 75, 100 mg/L), contact time (30, 60, 90 min), and process temperature (20, 30, 40 0C) on absorption of cephalexin were studied. In order to achieve the optimal experimental conditions, response surface methodology (RSM) model was used.
Results: The results showed that pH (p=0.0001), adsorbent dose (p=0.0001), initial concentration of cephalexin (p=0.0001), contact time (p=0.01), pH2 (p=0.0002) and pH (p=0.04) and initial concentration had a significant impact on the response variable. The optimum removal condition based on analysis of variance and the model was at the reaction time 90 min, pH 3, initial concentration 50 mg/L and adsorption dose 600 mg/L. Under these conditions, the removal efficiency of 81.1% was achieved.
Conclusion: The results showed that adsorption process with the mesoporous MCM-41 had a high efficiency on the removal of cephalexin from the aqueous environments.
M Ghodrat, E Asrari,
Volume 10, Issue 4 (3-2018)
Abstract
Background and Objective: Excessive consumption of antibiotics and the entrance of the potentially hazardous substances to the environment has become one of the environmental concerns. Today, adsorption is one of the efficient and reliable methods for the removal of this class of compounds. The aim of this study was to synthesize chitosan-Fe3O4 and to compare the efficacy of removing erythromycin antibiotics from aqueous humorous media by this adsorbent and chitosan.
Materials and Methods: The structural properties of the synthesized adsorbent were analyzed by TEM, PSA, VSM techniques. Various parameters including pH (1-11), contact time (0-60 min), adsorbent concentration (1-5 g/L), and initial concentrations of erythromycin (5-50 mg/L) was evaluated for the removal efficiency. For data analysis, Excel software was used. The equilibrium constant and the kinetic constants were calculated from the first-order kinetic model using Freundlich and Langmuir isotherms.
Results: The results indicated that increased pH and initial concentration of erythromycin increased the dose of adsorbents and the contact time of removal efficiency. The highest absorption efficiency at pH of 3 for both adsorbents, the contact time 30 min for modified chitosan and 50 min for chitosan, the dose of adsorbent 2 g/L for modified chitosan, and 3 g/L for chitosan and the initial concentration of erythromycin for each of the two adsorbents was 10 mg/L and the erythromycin adsorption by both adsorbents follows the Langmuir isotherm and the pseudo second order kinetics.
Conclusion: According to these results, chitosan modified with Fe3O4 can be used as a more effective adsorbent than chitosan for removal of erythromycin by adsorption method.
R Barati Rashvanlou, M Farzadkia,
Volume 11, Issue 1 (6-2018)
Abstract
Background and Objective: Ultrasonic disintegration is a pretreatment process before stabilization and dewatering that degrades sludge and changes its physical and chemical characteristics. The aim of this study was to investigate the effectiveness of ultrasonic in enhancing hydrolyses, stabilization and dewatering of municipal raw activated sludge.
Materials and Methods: The samples were taken from returned activated sludge and then they were exposed to ultrasonic (Frequency: 20 and 40 kHz) in different times (0.5, 1, 3, 5, 10, 15, 30, and 60 min). The effectiveness of ultrasonic for hydrolysis, stabilization and dewatering processes were determined with measuring TS, TSS, CST, SRF, VS, nVS, VSss, and VSsol.
Results: VSsol was increased by 73% in 15 min and at frequency of 20 kHz, whereas VSsol increas was100% at 10 min and 40 kHz. The reduction of VS was observed at 15 min and 20 kHz. Then after, it was reached 18% after 60 min. For 40 kHz, VS reduction started at 10 min and reached 24% after 60 min. Specific resistance of sludge at two frequencies of 20 and 40 kHz and contact time of 1 min were decreased by 25 and 20% respectively. The capillary suction time at the frequencies of 20 and 40 kHz and contact time of 1 min was decreased 28 and 21%, respectively.
Conclusion: The optimum effectiveness of ultrasonic in hydrolysis of organic matter of raw biological sludge was at the contact time of 10 min and frequency of 40 kHz. The highest stabilization at the frequency of 40 kHz was observed at 60 min contact time. The best condition for sludge dewatering was at frequency of 20 kHz and contact time of 1 min.
N Farrar, Sr Golestaneh, S Rasoulian,
Volume 11, Issue 3 (12-2018)
Abstract
Background and Objective: The sewer system is one of the important and suitable areas for the growth and reproduction of American Cockroach Periplaneta americana (L.) in Bushehr. This project was implemented for considering the high cost of spraying and environmental pollution.
Materials and Methods: In this study some commonly insecticides were tested in different doses to evaluate the effectiveness on cockroaches in sewer system. Three treatments including the combination of the insecticide with class B diatomaceous earth, solid silica gel and boric acid were evaluated in manholes of sewer system. In this regard, the Bushehr city was divided into ten clusters based on its sewer system and then, ten manholes were selected randomly from each area to survey and conduct field experiments. A random-cluster sampling method was used to generalize the results of the whole system. The mortality rate was corrected on control mortality with the Henderson-Tilton formula.
Results: Experimental insecticides spraying controlled up to 100 percent of cockroaches in the laboratory. However, using insecticide alone reduced the mortality rate in manholes over time. The results of statistical tests showed that the most effective method in destroying cockroach was the usage of the compounds of insecticide, mineral and non-chemical substances which caused mortality rate more than 90% up to 12 months.
Conclusion: As little as 50 g/manhole of a dust consisting of 5% silica gel, 35% boric acid, 60% diatomaceous earth with a commercial insecticide such as Deltamethrin sprayer provided more than 98% control for 12 months.
Y Abbasi, F Mirzaei, T Sohrabi,
Volume 11, Issue 3 (12-2018)
Abstract
Background and Objective: The main objective of this study was to evaluate the surface and deep distribution of Pb, Ni and Cu in the wastewater-irrigated area of south of Tehran using GIS and Hydrus. It was expected to find a comprehensive information of heavy metals distribution and their accumulation in the soil.
Materials and Methods: This study was carried out in wastewater-irrigated area of south of Tehran. Soil sampling from the top surface layer (0-15 cm) and wastewater channels was done. After sample analysis, ordinary Kriging method using different variogram in GIS was applied to explore the surface distribution of Ni, Pb and Cu heavy metals. Moreover, the deep percolation of heavy metals in the soil profile was simulated by Hydrus-1D in a duration of 210 days and the heavy metals concentrations in the soil were estimated.
Results: Exploration of the distribution of Pb using spherical model showed that the variation of this element was in the range of 20-70 mg/kg. This amount varied to 50-60 mg/kg for Cu and about 30 mg/kg for Ni. Moreover, the simulation of heavy metals deep percolation using Hydrus revealed that the most accumulation of heavy metals happened in the 0-15 cm soil surface layer and for deeper layer, this trend was descending.
Conclusion: Comparing the concentration of Pb, Cu and Ni with the maximum allowable amounts of WHO standards demonstrated that Pb concentration was more than the threshold limit. Finally, the applied models could simulate soil’s heavy metals content for both surface and deep distribution in the studied area.
R Mirzaei, M Yunesian, Ar Mesdaghinia, S Nasseri, M Gholami, E Jalilzadeh, Sh Shoeibi,
Volume 11, Issue 3 (12-2018)
Abstract
Background and Objective: Antibiotics are a group of emerging contaminants in the aquatic environment. Antibiotic residues threaten the human health and ecosystem in the low concentrations found in the environment. Hence, the present work has been conducted to investigate the occurrence and removal efficiency of most prescribed antibiotics including amoxicillin, penicillin, cefixime, cephalexin, ciprofloxacin, erythromycin and azithromycin detected in two urban wastewater treatment plants (WWTPs) in Tehran.
Materials and Methods: The present work is an applied research based on USEPA method no. 1694, to investigate pharmaceuticals residues in water by HPLC/MS/MS in year 2016. The differences between target antibiotics residues were investigated statistically. After the calculation of the removal efficiencies, the normality of the data was assessed. Then, parametric and non-parametric tests were used to compare the removal efficiencies in both WWTPs.
Results: There was not a significant difference between the influent and effluent concentrations of cefixime and azithromycin (in Ekbatan WWTP) and cefixime (in southern Tehran WWTP). There is a significant difference between the removal efficiencies of cephalexin (p=0.005) and erythromycin (p=0.002) in two WWTPs. The Highest median removal efficiencies were observed for cephalexin 94.41 and 99.47 in Ekbatan WWTP and southern Tehran WWTP, respectively.
Conclusion: In addition to the type of treatment processes, it is physicochemical properties of the selected compound has a significant influence on removal efficiencies.
M Hadi, M Solaimany Aminabad, M Amiri, M Arjipour,
Volume 11, Issue 3 (12-2018)
Abstract
Background and Objective: Treatment of hospital wastewaters has an important role in reducing the discharge of organics and pharmaceutical compounds into aquatic environments. Nowadays, advanced oxidation processes were extensively used for the removal of organic compounds from treated effluents. The study aimed to examine organic compounds removal from real treated effluent of a hospital treatment plant using a lab scale UV/H2O2/TiO2 process by optimizing the process.
Materials and Methods: The effluent characteristics including COD, TOC and DOC were measured and recorded. A hybrid advanced oxidation process (UV/H2O2/TiO2) was used for the removal of organic compounds. The experiments were designed using surface response methodology (RSM). The effects of the independent factors including pH, duration of UV irradiation, H2O2 and TiO2 concentrations on COD, TOC, DOC and the approximate cost of treatment were assessed by analysis of variance (ANOVA).
Results: The optimal condition was 7.2 for pH, 50 mg/L for H2O2, 100 mg/L for TiO2 and 19.65 min for irradiation time. This condition provided the maximum removal percentage for organic compounds with a minimum cost. The removal efficiency for TOC, DOC and COD were 63.9, 52.9, and 64.7%, respectively. The treatment cost was approximated to be $ 0.71 per one liter of the effluent.
Conclusion: Irradiation and H2O2 concentration had the greatest impact on the cost of the treatment. UV/H2O2/TiO2 process seems to be an expensive process for tertiary treatment of wastewater. However, further investigations are required to evaluate the cost effectiveness of the process for a full scale operation.
M Ansari, M Fahiminia, M Farzadkia,
Volume 11, Issue 4 (3-2019)
Abstract
Background and Objective: Rural wastewater management is recognized as one of the pillars of sustainable development. Therefore, the purpose of this study was to assess needs and prioritization of establishment of rural wastewater management facilities in order to supply a safe and alternative water source in the provinces of Iran experiencing severe water stress.
Materials and Methods: This is a cross-sectional descriptive study which was carried out in rural areas of the provinces with severe water stress (South Khorasan, Khorasan Razavi, Fars, Isfahan, Yazd, Semnan, Qom, Sistan and Baluchistan) in 2017-2018. In this study, the number of sample rural areas was calculated by Cochran method and the determination of the sample rural area was done by stratified sampling. The data related to the sample rural area was collected using a validated constructor questionnaire.
Results: The results of this study showed that the difference among all the studied provinces in terms of their priority in establishing rural waste water management facilities to provide a safe and alternative water source was very low. The provinces of Isfahan, Semnan and Fars were rated at 76 out of 100, while the provinces of South Khorasan and Sistan and Baluchestan scored 71 points.
Conclusion: With emphasis on comprehensive decision making criteria based on sustainable development, the results of this study showed that the provinces with severe water stress have a high priority regarding the establishment of rural sewage management projects in order to provide a safe and alternative water sources.
Mr Khani, Ah Mahvi, Ma Zazouli, Z Yousefi, Y Dadban Shahamat,
Volume 12, Issue 1 (5-2019)
Abstract
Background and Objective: Olive Mill Wastewater (OMWW) is one of the most polluted sanitary wastewaters that its ineffective treatment will cause severe pollution of the environment. In this study, OMWW treatment wasinvestigated using combined electrocoagulation and novel advanced oxidation process.
Materials and Methods: Biodegradability, efficiency and kinetics of removal of turbidity and organic matter from the OMWW by applying the operational parameters of electrocoagulation such as current density (0-0.77 A/dm2), type of anode electrode, reaction time (0-45 min) were investigated. Various types of advanced oxidation processes were performed to determine the the efficiency of removal of TOC and kinetics and biobegradability.
Results: The optimum condition for removing turbidity, BOD, TOC and consumed Iron anode electrod in electrocoagulation were 78%, 57%, 72% and 583 mg/ per liter of wastewater, respectively. Thus, the kinetic of TOC removal was first-order and was 0.027 min-1. The TOC removal efficiency of pretreated OMWW in oxidation processes of US, H2O2, SOP, O3 / H2O2, COP, COP/US and H2O2/COP/US were measured as 8%, 15%, 20%, 25%, 61%, 68% and 75%, respectively. The highest biodegradability index (BOD/TOC) in the COP/US/H2O2 process was increased 1.5 times.
Conclusion: The advenced oxidation process of COP/US/H2O2 follwed by electrocagulation demonstrated an effective treatment of OMWW and improved its biodegradability. Therefore, this process can be used for efficient treatment of OMWW in olive and similar industries.
S Fallah Jokandan, M Yegane Badi, A Esrafili, A Azari, E Ahmadi, H Tarhandeh, M Kermani,
Volume 12, Issue 2 (9-2019)
Abstract
Background and Objective: The activities of various industries produce a wide range of pollutants and toxic compounds. One of these compounds is the catechol, a cyclic organic compound with high toxicity and resistant to degradation. Therefore, the purpose of this study was to investigate efficiency of powder activated carbon magnetized with Fe3O4 nanoparticles in the removal of catechol from aqueous solutions by response surface methodology.
Materials and Methods: The co-precipitation method was used to synthesize magnetic powder activated carbon and its properties were analyzed by SEM and XRD analysis. Then, the effect of the parameters such as pH, contact time, absorbent dose, initial concentration of catechol and temperature on the efficiency of adsorption process were investigated using a response surface methodology (Box–Behnken). The residual concentration of catechol was measured by HPLC at 275 nm.
Results: The results showed that the maximum efficiency of the adsorption process was obtained at concentration of 20 mg/L, pH=3, contact time 90 minutes, at 25 °C and absorbent dose of 1.5 g/L. The study of isotherm and kinetics showed that the experimental data of the catechol adsorption process correlated with the Langmuir and pseudo-second order models, respectively. Thermodynamic study of the reaction also expresses the Exothermic and Spontaneous process.
Conclusion: The results showed that the adsorption process using powder activated carbon magnetized with Fe3O4 nanoparticles at acidic pH had better efficiency. As a result, the studied process as an effective, rapid and inexpensive method for removal of catechol from aqueous solutions is proposed. Due to its short reaction time, it is economically affordable process.
M Khalaji, Sa Hiseini, R Ghorbani, N Agh, H Rezayi,
Volume 12, Issue 2 (9-2019)
Abstract
Background and Objective: Nutrient-rich effluents (mainly nitrogen and phosphorus) may lead to algae blooms and many harmful effects in aquatic environments. Micro-algae have been more effective among the various methods used for the removing of nutrients from wastewater. Microalgae Chlorella vulgaris has specific characteristics such as rapid growth, resistant to systems manipulation, simple and inexpensive production technology, as well as the rapid uptake of nutrients such as phosphate and nitrate.
Materials and Methods: In the present study, two concentrations of chlorella vulgaris microalgae (13 and 26 million cells/mL) were injected into dairy effluent, diluted using distilled water by 25, 50 and 75%, and the amount of nutrient removal and microalgae growth were examined during the growth period.
Results: Results indicated that different concentrations of algae at various percentages of dilution (25, 50, 75%) had a significant effect on the removal of nutrients and algal growth (p<0.05). The absorption of nutrients (nitrate, phosphate and ammonia) were 57.01, 51.84 and 43.15 percent respectively that containing lower density of initial algae compared to the treatments of 2nd group (29.15, 51.84 and 43.15 percent) with higher algae concentration. In both algal concentrations, the highest percentage of phosphate and ammonia adsorption were in dilution of 25% effluent and the highest percentage of nitrate adsorption were in the first group with 50% dilution and in the second group with 75% dilution.
Conclusion: The more percentage of nutrients (nitrate, phosphate, ammonia) was eliminated compared to the second group (26 million cells / mL) when the microalgae concentration (group I) was 13 million cells / mL. Absorption of nutrients was decreased by increasing the concentration of microalgae. Regarding to the percentage of nitrate adsorption, the higher absorbance in the dilution was occurred at the highest concentration of algae.
Sh Goodarzi, Gh Shams Khoramabadi, M Esmaty, Ma Karami, A Hossein Panahi,
Volume 12, Issue 2 (9-2019)
Abstract
Background and Objective: Wastewater from pharmaceutical industry has high chemical oxygen demand as a result of the presence of organic drugs and antibiotics. In order to meet the environmental requirements, several treatment methods like chemical and electrochemical methods have been widely applied due to their high ability to remove organic compounds from pharmaceutical wastewater. Therefore, the present study aimed to evaluate the efficiency of chemical coagulation/Electro-Fenton treatment method to degrade the organic matter-containing pharmaceutical industry wastewater.
Materials and Methods: The experimental tests were carried out using batch mode. The chemical coagulation process was evaluated as a function of aluminum chloride concentration (25-300 mg/L) and pH (3-10). The effluent from chemical coagulation process was transferred to Electro-Fenton reactor. Effects of H2O2 concentration (100-4000 mg/L), reaction time (up to 120 min), voltage (10-30 V), and pH (3-10) were evaluated. The removal efficiency was determined in term of COD removal.
Results: The results showed that the highest removal of COD in the chemical coagulation was 49% (coagulant dose of 200 mg/L, and pH of 7). In addition, the Electro-Fenton process could be eliminating of 93.5% of COD at the optimum conditions concentration (100 mg/L H2O2, voltage of 20, pH of 3, and contact time of 30 min).
Conclusion: According to the results, it can be concluded that the combination of chemical and electrochemical processes was found to be effective methods for treatment of pharmaceutical wastewater in comparison to the application of each process separately. To reach to the maximum removal efficiency, the environmental parameters should be carefully controlled at their optimum values in each single process.
R Salmasi, A Behbahaninia, Ar Ostadrahimi,
Volume 12, Issue 2 (9-2019)
Abstract
Background and Objective: Heavy metals fixation in-situ by using inorganic amendments is a method for immobilization of polluted soils. The goal of this research was to determine efficiency of five amendments for heavy metals fixation of waste-water-irrigated soils around Tabriz city.
Materials and Methods: Cadmium, Pb, Cu, Ni, and Zn- containing solutions were added to 0.5 gram of five amendments including calcite, hematite, zeolite, illite, and bentonite. 10 soil samples from around of Tabriz city were taken. After shaking the samples, the concentrations of the five elements were determined in the filtered solution by using atomic absorption instrument. Retention capacity percentages of these elements were calculated, and the best amendments were determined by using Dunkan method.
Results: There were differences of heavy metals retention between amendments. Calcite had the highest retention of Cd (91%), Ni (78%), and Zn (94.7%); hematite had the highest Cu (90.5%) and Pb (94.3%); and illite showed the lowest retention of the 5 elements. Calcite, zeolite, bentonite, and hematite had significant higher retention capacities of Cd, Ni, and Zn in compared to 10 the soil samples.
Conclusion: Among the studied amendments, retention capacities of calcite and hematite for the five elements were higher than the remaining ones for addition to the soil. These two amendments can cause low uptake and low accumulation of the elements in agricultural crops in polluted soils.
M Gholizadeh, M Nosrati,
Volume 12, Issue 3 (12-2019)
Abstract
Background and Objective: Algal wastewater treatment is a new and economic technology to remove and recycle nutrients from wastewater. In order to investigate the effect of vinasse on microalgae growth and also the effect of its growth on nitrogen and phosphate removal in a mixture of urban wastewater and vinasse, the growth of Spirulina platensis was studied.
Materials and Methods: Growth ability of spirulina in the urban wastewater and the effect of vinasse on growth rate was investigated by the calculation of biomass. The effect of concentration of vinasse, intensity of light and light-dark cycle on growth rate were studied by DESIGN EXPERT and CCD method. By selecting the optimized conditions, rates of nitrogen, phosphate and COD removal was investigated at the end of the growth period.
Results: The results showed that adding vinasse to wastewater increased the growth rate and the highest amount of biomass of 3.19 mg/mL was obtained in the sedimentary stream containing 0.25% vinasse. By evaluating the effect of vinasse concentration, intensity of light and light-dark cycle on growth rate, optimal conditions at vinasse concentration 0.4% (v/v), light intensity of 5000 lux and light period of 10 hours, 480 (mg/L) of biomass was obtained. The percentage of removal of nitrogen, phosphate and COD was 63%, 97% and 73% respectively.
Conclusion: The results of this study indicated the capability of urban wastewater and vinasse in order to replace Zarouk's culture medium for growth of Spirulina microalgae. These microalgae were able to remove high percentage of nutrients in the wastewater.
H Niknejad, M Farzadkia, A Esrafili, M Kermani,
Volume 12, Issue 4 (2-2020)
Abstract
Background and Objective: 2,4 dinitrophenol is observed in sewage produced from chemical and petrochemical industries. Contamination of drinking water with these pollutants causes toxicity, health problems and change in taste and odor. The present study was developed to evaluate the efficiency of removal 2,4-DNP through dried sludge adsorbent and modified calcium chloride sludge adsorbent.
Materials and Methods: At first, sludge was dried at temperature of 60 °C. Next, CaCl2 was used to improve adsorption capacity. The removal efficiency of 2,4 dinitrophenol were determined by HPLC at wavelength of 360 nm. The effects of influencing factors including pH, initial pollutant concentration, contact time, and adsorbent dose were examined.
Results: The optimum pH of adsorption for both adsorbents was found to be 7. The optimum concentration of 2,4-DNP was 10 ppm. The results obtained from the present research showed that the removal of the contaminant using dried and modified sludge sorbent was increased from 72.6% to 86% at a dosage of 1.5 g. The adsorption kinetics were fitted with the pseudo second order kinetics model for both adsorbents. The isotherm data also showed that the adsorption of this pollutant on both adsorbents is fitted with the Freundlich model.
Conclusion: Results obtained from the present study indicated that the efficiency of the modified sludge ash is more than the non-modified sludge in 2,4 dinitrophenol removal. This can reduce adsorbent consumption in industrial treatment plants.
