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Showing 15 results for Water Treatment


Volume 1, Issue 1 (3-2023)
Abstract

Treatment of organic leachate is one the most controversial topics around the world which led this study to assess the efficiency of the combined oxidation and adsorption treatment (COAT) process in the treatment of leachate by considering local experiments. The removal of effluent parameters (TDS, COD, BOD) was enhanced by oxidizing the GAC surface as a catalyst with NaOH before the process and by ozone within the procedure as well. Assessing the interacting effect of operating variables (i.e., ozone concentration, GAC density, reaction time and pH) provides valuable information for optimization. Response Surface Methodology (RSM) was employed. The optimized model’s circumstances are the reaction time of 30.77 min, ozone dosage of 141.29 mg/l, pH of 7.2, and the GAC density of 1.29 gr/cm3 with the predicted removal percentage of 51.63%,62.84% and 56.13% for TDS, COD and, BOD respectively.
 

Volume 1, Issue 1 (5-2025)
Abstract

In recent years, the increasing presence of antibiotics particularly ciprofloxacin (CIP) in aquatic environments has raised serious environmental and health concerns. This study investigated the efficiency of titanium dioxide (TiO₂) nanoparticles activated by ultraviolet (UV) light in removing ciprofloxacin from aqueous solutions. Experimental design was carried out using Design Expert software, and the effects of variables such as pH, reaction time, and initial drug concentration were evaluated. The results showed that increasing reaction time and decreasing initial concentration significantly improved the removal efficiency. The optimal pH range for maximum removal was found to be between 5 and 7. Additionally, the photocatalytic system used in this study demonstrated high performance, low energy consumption, and the ability to degrade the pollutant without the need for additional chemicals. These findings suggest that TiO₂-based photocatalysis is an efficient and environmentally friendly method for treating wastewater containing antibiotics.

Volume 2, Issue 1 (3-2014)
Abstract

To compare the seed characteristics in accessions of Atriplex canescens under exclosure and non-exclosure conditions, two even-aged sites were selected with an area of 400 ha as the exclosure and 1000 ha as non-exclosure area. To conduct the study, 30 species were randomly selected in autumn 2009 in reference area of the sites and seeds were collected. Some important seed characteristics were studied in the laboratory. Data analysis was conducted using SPSS 17 software and mean comparisons were performed by Duncan's Multiple Range Tests. Results showed that the winged seeds did not germinate under all studied treatments in both sites. Moreover, maximum seed germination was recorded for the seeds soaked in cold water for 24 hours and placed in the shade for 48 hours. According to the results of the independent t-test, no significant differences were observed for germination percentage, germination rate, and vigor index in both sites at both 1 and 5% probability levels. In other words, the seeds collected from the exclosure and non-exclosure areas were similar in terms of the mentioned characteristics. However, seed yield, 1000-seed weight and seed moisture content showed significant differences at 1% probability level with higher amount in exclosure area.

Volume 4, Issue 13 (7-2007)
Abstract

  In this experiment the effects of preharvest calcium chloride and postharvest hot water treatment as well as the use of polyethylene bags for packaging on the quality improvement of pomegranate fruit during cold storage were studied. For this purpose Calcium chloride was sprayed at two levels on August 2004 (1% and 2%). Pomegranate fruits of Malas - Torsh cv. was harvested at fully ripen stage and treated with hot water (45, 50 and 55C for 20 minutes, 1 minute and 30 second espectively). Thereafter each fruit was warped up in a polyethylene bag and stored in cool store room with 1C and relative humidity of 85% for 3 months. The experiments were conducted using a completely randomized design of three replicates. The results indicated that fruits wrapped with polyethylene had a significant effect on preventing weight loss, improving the appearance as well as marketability of fruits during storage, while showing no effect on pH, TSS and fruit dry matter. Also it was observed that fruits treated in 50'C hot water showed significant improvement of quality while treatment with 45C hot water failed to show such effects. In total, a combination of Calcium chloride and polyethylene bag packaging along with 50C hot water treatment caused improvement in the general quality of stored fruit and decreased fungi infection and chilling index.

Volume 6, Issue 1 (4-2018)
Abstract

Aims: Karun River, which is the largest river in Iran, represents a unique ecosystem. However, increased anthropogenic activities result in the formation of this river is seriously affected by a large range of pollutants especially the heavy metal pollutants which may be toxic to human and aquatic fauna. Therefore, there is a need for continuous monitoring of pollution levels in the river.
Materials & Methods: In this study, water, sediment, and algae samples were collected from six different stations along the course of the river in September 2015 to investigate the quality of Karun’s River in terms of heavy metals (Pb, Zn, Cr, and Cd) at the basin of drinking water treatment in Ahwaz and Mollasani cities. After drying and digestion of samples, heavy metal concentrations were determined using an atomic absorption spectrophotometry (Perkin Elmer-Analyst 300).
Findings: The highest concentration of trace metals was found in sediment samples with Zn having the highest mean concentration values in all stations. The heavy metal concentrations in the downstream indicated an increase in the pollution load due to the flow of water from upstream to downstream of the river resulted in the movement and accumulation of all contaminants to the river in the downstream; hence, there was the highest concentration
of metals in basin of the Kut Abdollah treatment (downstream) and the lowest in Mollasani (upstream).
Conclusion: Comparison of the concentration of metals in the sediments with some universal standards including EPA3050 and the criterion of sediments quality standard from NOAA and Canadian Environment Agency showed that the concentration of chromium and cadmium in stations was higher than the allowable limit of EPA3050 standards and some environmental standards of Canada among all metals. Since algae samples have been able to accumulate a significant amount of heavy metals, therefore, these are suitable bio-indicators to determine the concentration of heavy metals in this aquatic ecosystems.

Volume 6, Issue 3 (12-2022)
Abstract

Research subject: Osmosis membrane bioreactor is one of the best industrial wastewater treatment methods. The main advantage of using osmosis process is its operation at low hydraulic pressures which has a better performance in removing pollutants and low energy consumption than other methods                        
Research approach: In this research, Nano porous Titanium dioxide powder with a specific surface area and anatase wall was synthesized through a thermal process using cetyltrimethylammonium bromide (CTAB) as a surfactant directing agent and a pore-creating agent.Ultrafiltration nanocomposite membranes were made using modified titanium dioxide (TiO2) (MT) and polysulfone (PSf) by phase the inversion method. The morphology and structure of the prepared membranes and nanoparticles were investigated using by atomic fourier transforms infrared spectroscopy(FESEM), X-ray diffraction (XRD) and transmission electron microscopy (TEM). In this research, bovine serum albumin (BSA) was used as simulated wastewater for the feed solution. The fabricated ultrafiltration membranes were tested in osmosis membrane bioreactor (OMBR) system due to lower energy and fouling. 0.6 % solution of poly (sodium 4-styrene sulfonate) was used as an osmotic solution. Comparative separation performance and antifouling properties of both nanocomposites in several analyzes such as water contact angle measurement, pure water flux and filtration of different concentrations of bovine serum albumin solution. BSA and fouling resistance have been investigated


Main results:  TThe results that Due to the addition of MT nanoparticles to the polymer matrix, the hydrophilicity and surface energy of the membrane increased, which led to the improvement of the membrane performance. The membrane containing 1% titanium oxide nanoparticles showed the best result. For example, for feeding with a concentration of 200 ppm, the water flux increased from 20 to 38.5 L/ m2 h, and the percentage of returning lethal solution decreased from 19.6 to 30 g/ m2 h. The flux recovery in this membrane was 96%, which indicates the antifouling property of the modified nanocomposite membrane.                                                                
              

Volume 8, Issue 31 (8-2011)
Abstract

In this study the effect of hot water, acetic acid and sodium chloride solutions on the accelerated ripening of Mazafati date cultivar was investigated. Except for the cold storage control (Blank), other samples (control sample and samples that immerged in water, acetic acid (0.5, 1.5 and 2.5%) or NaCl (1, 2 and 3%) solutions with 60˚C for 5 min) were incubated at 39±1 ˚C for 80 hrs. The results indicated that incubation was the main factor in ripening of the date and about 85% of the control samples ripened only by incubation. Acetic acid and NaCl solutions had complementary and accelerating effects. Total solids, total soluble solids and acidity of the samples increased while the pH, water insoluble solid, hardness and color parameters (L*a*b*) decreased during ripening for all samples except for blank sample. Overall, the treatment by hot acetic acid solution (0.5%) followed by incubation at 39±1˚C can be used as a good candidate for accelerated ripening of Mazafati date.

Volume 11, Issue 1 (3-2020)
Abstract

The waste produced by households, industry and factories to use as wash water and cooling systems and equipment, is caused environmental complications. Waste created a suitable environment for the growth of odor and pathogenic bacteria. This study aimed to isolate microorganisms in the wastewater and use them for the reduction of BOD (biochemical oxygen demand) and COD (chemical oxygen demand).The samples were collected aseptically from different parts of wastewater of herbal distillation industry. The bacterial strains were isolated from the samples in LB media. The isolates were distinguished based on the morphology and biochemical characteristics. Among the total 69 isolates, four isolates were selected to measure the ability to reduce BOD and COD and added to the waste water. Reduction of BOD was measured using BOD meter. Also, COD was determined by titration method. The isolates were identified by biochemical tests. The amount of BOD and COD reduction after adding selected strains to wastewater was 47.43 - 71.82% and 44.79 - 56.5% respectively. Also, the consortium of bacterial strains showed better ability to reduce BOD and COD (38.32-57.29%and 76.6-83.21% respectively). The results determined that wastewater contains bacterial strains which have shown significant reduction in BOD and COD and organic matter decomposition in wastewater and reuse it in agricultural and industrial sectors. Therefore, we can use these bacteria for wastewater treatment.

Volume 12, Issue 4 (12-2024)
Abstract

Aims: In this study, we evaluated the performance of direct microbial fuel cells using citric acid wastewater as a substrate under different concentrations of MLSS 1000 mg.L-1 and 3000 mg.L-1. 
Materials & Methods: Aspergillus niger yeast was used as a microorganism over 4 days and nights of this experiment. A Nafion membrane was used for proton transfer, and graphite plates were used for electron transfer. COD removal efficiency, maximum open circuit voltage, power, and current density were evaluated. 
Findings: The general trend of energy production and removal efficiency showed that energy production increased with increasing MLSS. The maximum of these variables was recorded for MLSS of 3000 mg.L-1, achieving a removal efficiency of 93%, an open circuit voltage of 500 mV, and power and current density of 24345 µW.m-2 and 444 mA.m-2, respectively. 
Conclusion: Our results showed that the designed MFC suits wastewater treatment and energy recovery.


Volume 12, Issue 48 (9-2015)
Abstract

There is not enough information about postharvest physiological behavior and optimum storage temperature of cultivated persimmons in Karaj region of Iran. In this study, persimmon fruit, cv. Karaj, was harvested at mature stage and was treated with hot waters at 45 and 50°C for 20, 30 and 45 min. Besides, one lot of fruit was bathed at 25°C for 30 min as control treatment. The physiological behaviors of treated fruits were monitored during 4 months storage at 0, 2 and 5°C. Results showed that severity of symptoms, such as; skin browning index, fruit softening, fungal disease incidence and loss of color indices (L*, a*, b*), were higher in storage at 2 and 5°C than storage at 0°C. Therefore, ʻKarajʼ persimmon was tolerant to 0°C for storing purpose. On the other hand, hot water treatments at 45°C for 30 and 45 min and 50°C for 20 min maintained fruit firmness and color properties, and controlled disease incidence better than that of control and hot water treatment at 45°C for 20 min. However, hot water treatment at 50°C for 30 and 45 min, in spite of maintaining suitable colour properties, contrary with other effective treatments caused to fruit skin browning and had notociable fungal disease. Therefore, hot water treatments at 45°C for 30 and 45 min and 50°C for 20 min are the recommendable treatments for increasing postharvest life of Karaj persimmon.  
Ashkan Banan, Mohammad Reza Kalbassi, Mahmoud Bahmani,
Volume 13, Issue 4 (11-2024)
Abstract

The indirect application of silver nanoparticles (AgNPs) in controlling the common fungal infection during the incubation period of Persian sturgeon -saprolegniasis - was investigated in this research. Filters containing 0.2%, 0.5% and 1% of AgNPs in two states without agent and with aminopropyltriethoxysilane (APTES) coupling agent along with the control treatment (without filter) were the treatments investigated in the present study. The results showed that in the first 48 hours of incubation, which corresponds to embryonic growth before the start of neurulation, despite the start of contaminating the water in the incubators with Saprolegnia fungus, fungal infection was not seen in any of the investigated treatments. The results of measuring the amount of silver released from the studied filters at the end of the first 12 hours of incubation showed that the amounts of silver released in the water in the treatments of 1% AgNP filters without APTES and with APTES were significantly higher than other filters containing AgNPs. This trend was repeated at the next sampling rounds (48 and 96 hours) with the difference that the release rate was significantly higher only in the 1% AgNP-APTES filter treatment. In the treatment of AgNP-APTES filters, the percentage of hatching showed a significant increase compared to the control filter treatment.

Volume 16, Issue 3 (10-2016)
Abstract

Surface water contains various type of suspended impurities that cause turbidity and color. Coagulation is the main process of integrating fine particles and turn them into larger particles. In this study, replacement of the modeling methods by time-consuming and expensive experimental techniques such as JAR test has been discussed. For this purpose, two models of Feedforward and radial basis of artificial neural networks and Adaptive network-based fuzzy inference system and the various kinds of fuzzy regression analysis to predict the ultimate extent of turbidity after coagulation and flocculation process in 3 and 4 Tehran water treatment plants, were studied. The coagulant used in the treatment plant was poly-aluminum chloride (PAC) and the type and concentration of coagulant, pH and turbidity of the raw water, was opted from the basic information. Radial basis model due to the possibility of automatic raising of hidden layer’s neurons to achieve performance function with minimum error, is highly capable in simulating the process of coagulating. Unlike Feedforward networks, radial basis networks required a smaller number of neurons, and also had the ability to change parameters to achieve the desired results. Increasing the number of hidden layer’s neurons and normalizing the input data to the network enhanced the predictability of artificial neural networks. The study also generalize Feedforward networks to predict data validation and correction of the increasing of performance function. Due to the uncertainty which caused by human error in the laboratory, adaptive network-based fuzzy inference system and fuzzy regression, in which the data sets in the form of fuzzy, were used. The results showed that artificial neural networks and fuzzy regression analysis had more ability in simulating the coagulation process and turbidity removal in different experimental conditions rather than adaptive network-based fuzzy inference system and had the ability to replace the JAR test with time-consuming and expensive methods. The best network built to predict the filtered water turbidity in this study was feed forward network with two hidden layers and 6 and 8 neurons and Tansig and Purelin transfer functions respectively in the first and second layers, using normalized data with performance function. This network is able to predict the coagulation process with a Correlation Coefficient of 0.96 and 0.99 Agreement Index and root mean square error 0.0106. Best predicting done by regression analysis using fuzzy quadratic function. This function was able to predict the data validation with a correlation coefficient, and Agreement Index and root mean square error, respectively, 0.94, 0.96 and 0.75. adaptive network-based fuzzy inference system with the use of Gaussmf membership functions for raw water turbidity and pH input ,and type and Trimf had best efficiency to apply coagulant concentration data into network and estimated the filtered water turbidity with correlation coefficient of 0.89, Agreement Index of 0.91, and squares error of 1.02. This system showed that increasing initial turbidity caused removal efficiency increased and the best impaction of coagulation process for the removal of turbidity would be occurred in the range of pH, 7.6 to 8. The best efficiency in operation condition was determined 99.5% in initial turbidity of 160 NTU, pH=8 and 19 mg/L dosage of PAC coagulant type I.

Volume 17, Issue 2 (7-2017)
Abstract

Composting is certainly one of the most natural types of recycling process. One of the problems during this process is the management of leachate that adversely affects human and ecological health in the area. Leachate is a complex organic compound which is difficult to be degraded biologically by conventional methods. Advanced oxidation processes (AOPs) have been widely studied for the degradation of diverse types of industrial wastewaters. The purpose of the study was aimed to evaluate the efficiency of hydrogen peroxide with ultraviolet light (H2O2/UV) for the treatment of high chemical oxygen demand (COD) strength compost leachate, color and turbidity using response surface methodology (RSM) under central composite design (CCD). The various operation conditions such as initial pH, dose of hydrogen peroxide, and UV-contact time was examined in order to optimize the maximum COD and color removal and turbidity of the compost leachate. The total number of 20 experimental runs was set. Optimal condition obtained for H2O2/UV process were initial pH 7.5, dose of hydrogen proxide 2.3 mL/L, and UV-contact time 95 min. In these conditions, the removal of COD and color and turbidity for H2O2/UV process was 12.32%, 20.83%, and 8.68 NTU, respectively. The results indicated that the H2O2/UV process has been successful in reducing turbidity but in COD removal efficiency is not well. Composting is certainly one of the most natural types of recycling process. One of the problems during this process is the management of leachate that adversely affects human and ecological health in the area. Leachate is a complex organic compound which is difficult to be degraded biologically by conventional methods. Advanced oxidation processes (AOPs) have been widely studied for the degradation of diverse types of industrial wastewaters. The purpose of the study was aimed to evaluate the efficiency of hydrogen peroxide with ultraviolet light (H2O2/UV) for the treatment of high chemical oxygen demand (COD) strength compost leachate, color and turbidity using response surface methodology (RSM) under central composite design (CCD). The various operation conditions such as initial pH, dose of hydrogen peroxide, and UV-contact time was examined in order to optimize the maximum COD and color removal and turbidity of the compost leachate. The total number of 20 experimental runs was set. Optimal condition obtained for H2O2/UV process were initial pH 7.5, dose of hydrogen proxide 2.3 mL/L, and UV-contact time 95 min. In these conditions, the removal of COD and color and turbidity for H2O2/UV process was 12.32%, 20.83%, and 8.68 NTU, respectively. The results indicated that the H2O2/UV process has been successful in reducing turbidity but in COD removal efficiency is not well. The results indicated that the H2O2/UV process has been successful in reducing turbidity but in COD removal efficiency is not well.

Volume 17, Issue 2 (7-2017)
Abstract

Introduction: Petrochemical industry is one of the major industries playing significant role in the economy of Iran. In general, petrochemical effluents contain various contaminants including suspended solids, organic matters, oil and grease, metal salts, sulfide, ammonia, hydrocarbons, cyanides, volatile organic compounds (VOCs) and other toxic substances. In most of petrochemical complexes, wastewaters are treated by activated sludge process along with the oil/water separation systems as a pretreatment. Since the performance evaluation of wastewater treatment plant is required to assess the effluent quality, to meet higher treatment requirement and to know the feasibility of handling higher hydraulic and/or organic loadings, this study was conducted to evaluate the performance of a full-scale petrochemical wastewater treatment plant.
Materials and methods: Wastewater treatment system consists of a screening unit, an API, an equalization basin, coagulation and flocculation, DAF system, aeration tanks, primary and secondary clarifier and filtration. The treatment plant was designed to treat the wastewater generated from different units of petrochemical complex with reuse purposes of treated effluent. To evaluate the performance of the treatment plant, 12-h composite flow weighted samples were carried out in 4 days within 6 month and were analyzed for COD, BOD5, TDS, TSS, phenol, cyanide, oil, ammonia and TKN in accordance to standard methods. Microbial structure of activated sludge was also evaluated. Overall performance of the plant and the performance efficiency of each unit were calculated.
Results: According to the results, the actual average influent flow was significantly lower than the average design flow based on the long-term data and our measurements. This increases the hydraulic retention time (HRT) in all units in the WWTP. Based on the results, the values of COD, BOD5 and TSS in the influent and effluent were 1319±230, 967±491 and 227±174 mg/l and 73.6±19.6, 33.6±25.9 and 6.4±5.9 mg/l respectively. The ratio of BOD5/COD was calculated about 0.58 indicates a good potential for biodegradability of the wastewater. The results also revealed that 68.5% removal of COD and 81.9% removal of BOD5 have been occurred in preliminary and primary units while; these units are usually designed for the elimination of oil and suspended solids as well as the equalization of quantitative and qualitative parameters of the influent. At an organic loading of 0.48±0.15 kg/m3.d the removal efficiencies for COD and BOD5 in biological unit were calculated about 37 and 46% respectively. The mean value of MLSS within the biological reactor was 1463 mg/l. In addition, the mean plus standard deviation values of MLSS measured in returned activated sludge (RAS) were 2323 ± 1080 mg/l. According to the daily average concentrations of COD in the effluent of the WWTP, in some cases within the study period, the COD values were exceeded from national discharge standards. Microbial analysis showed that among the isolated bacterial strains, the genus belonging to Alcaligenes, Pseudomonas, Bacillus and Moraxella as heterotrophic nitrifying bacteria was identified as predominant strains in biological unit.
Conclusion: Based on the results, in 64% of our measurements (135 days from 209 days of study period), the daily average effluent COD values were above national guidelines for surface water discharge (60 mg/l). In 3% of the time during the study period, the daily average values of COD in the effluent were more than 200 mg/l. The results also indicated that the average effluent concentration of oil was significantly higher than the expected design value.

Volume 23, Issue 5 (11-2023)
Abstract

Industrial progress has ushered in the production of a diverse array of pollutants, encompassing both organic and non-biodegradable substances, such as hydrocarbon compounds derived from petroleum. As the discernible environmental ramifications of these pollutants continue to escalate, the quest for efficacious methodologies for wastewater remediation assumes paramount importance. Among the emergent technologies, plasma technology has garnered considerable acclaim due to its capacity to obliterate a myriad of pollutants. Plasma, which ensues from the application of high voltage to either a gaseous or liquid medium, engenders profoundly reactive species capable of dismantling intricate organic compounds. Similarly, ozone, an exceedingly potent oxidizing agent, has long commanded recognition for its aptitude in the degradation of pollutants. Its robust oxidative attributes render it an invaluable instrument in the realm of wastewater treatment. Ozone treatment entails the infusion of ozone gas into the contaminated aqueous medium, whereupon it engages pollutants in a transformative reaction, rendering them into less deleterious byproducts. By amalgamating the ozonation process with plasma technology, we can harness the merits of both modalities and achieve synergistic effects. This hybridized approach proffers several advantages vis-à-vis individual treatment methodologies, including augmented pollutant removal efficiency, diminished treatment duration, and amplified energy efficiency. The plasma-ozonation process exploits plasma's propensity for the generation of reactive species, capable of reacting with the organic constituents in wastewater. The ensuing ozonation phase augments the degradation of these constituents, engendering a more efficacious and comprehensive removal process. Prior investigations have scrutinized the efficacy of ozone and plasma in isolation for the eradication of p-nitrophenol, a ubiquitous organic pollutant encountered in industrial wastewater. These inquiries have methodically examined various parameters to ascertain their influence on pollutant removal efficiency. Factors such as applied voltage, ozone dosage, initial pH, reaction duration, and initial solution concentration have been subjected to meticulous scrutiny to optimize the treatment regimen. In the present study, we have devised an innovative mathematical model to probe the interplay between these two independent variables: plasma technology and ozonation. The model incorporates a quadratic equation and employs analysis of variance (ANOVA) to gauge the significance of each variable and discern the optimal conditions for pollutant removal. Through scrutiny of the model, we have ascertained that the pinnacle of removal efficiency, surpassing 95%, materializes under specific parameters. These parameters encompass an applied voltage of 14 kV, an oxygen flow rate of 6 L/min, an initial pH of 10, a reaction duration of 6 minutes, and an initial concentration of 200 mg/L. These revelations offer valuable insights into the operational parameters that yield superlative results for pollutant removal within the context of the plasma-ozonation process. The efficacious integration of ozone and plasma technologies in wastewater treatment proffers a promising panacea for the elimination of p-nitrophenol pollutants and sundry other organic constituents. By fine-tuning the process parameters in alignment with the model's recommendations, we can attain exceptional levels of pollutant elimination whilst concurrently minimizing energy consumption and treatment duration. This research significantly contributes to the perennial endeavors aimed at fashioning sustainable and efficient remedies for industrial wastewater treatment, endowing valuable perspectives for their future deployment and widescale application in industrial settings.




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