Showing 13 results for Las
M Ahmadi, H Ganjidoust, B Ayati,
Volume 1, Issue 2 (3-2009)
Abstract
Background and Objectives: Upflow Sludge Blanket Filtration (USBF) system is a modification of the conventional activated sludge process that incorporates an anoxic zone with an upflow sludge blanket filtration clarifier in one bioreactor. It has no inherent capacity limits and is used in a wide range of applications in municipal, industrial and agricultural wastewater treatment. The main objective of this study was to evaluate the performance of a continuous USBF reactor for the treatment of sugar industrial wastewater.
Materials and Methods: Sixty liter laboratory pilot scale plant was made of plexiglass consists of 14 liter anoxic zone, 38 liter aerobic zone and 8 liter clarifier. Used molasses for raw wastewater was obtained from Varamin Sugar Company. During the study, the wastewater has been initially fed to anoxic zone of the bioreactor. It mixed with recycled activated sludge returned from the clarifier and the mixed liquor entered into aerobic zone of the bioreactor. From aeration zone, the mixed liquor passed through the sludge zone at the bottom of the clarifier which was then separated by upflow sludge blanket filtration and then the clear water discharged from the system. To complete the internal circulation loop, collected activated sludge at the bottom of the clarifier was recycled to the anoxic zone.
Results: Experimental studies indicated that average removal efficiency of COD with HRTs from 21 to 26 hours in the aerobic zone and from 8 to 10 hours in the anoxic zone were from 77 to 97 percent depended on input feed (1000 to 30000 mg/L).
Conclusion: USBF as an advanced biological process had a proper COD removal efficiency for the biological treatment of sugar industries wastewater compared to other researchers methods.
M Pirsaheb, A Almasi, A.a Zinatizade, R Khamutian, S Delangizan,
Volume 4, Issue 2 (9-2011)
Abstract
Background and Objectives: Linear alkyl benzene sulfonates are widely used as surfactants in formulated detergent products. Because of their use in household and industrial detergents, LAS is discharged into wastewater collection systems and subsequently entered to wastewater treatment plants. Therefore, it is important to determine the concentration of LAS with accuracy. They are usually determined by standard method which is time-consuming,tedious and requires great quantities of chloroform. IN 2006 E.Jurado et al proposed a simplified method for measurement of LAS. In the present work the standard method and E.Jurado simplified method was compared economically.
Material and Methods: In this work NPV method was used for accounting the cost of initial investment, consumable material, non-consumable equipment and annual cost of staff and finally Net Present Value was calculated for them separately. The rate of interest was considered 15%.
Results: calculation showed initial investment, annual cost of staff and materials for standard method 13351981, 499968 and 1710981 RLS, respectively. And these costs for simplified method were 12048202, 83328 and 58202 RLS, respectively. Finally NPV for standard method and simplified method were equal to 30360709 and 14681848 RLS.
Conclusion: The method proposed by E.Jurdo et al is simple, time consuming and more economical than standard method .This technique can be suggested applying to the routine measurement of LAS in wastewater treatment plants.
Ali Kazemi, Habibollah Younesi, Nader Bahramifar,
Volume 6, Issue 4 (3-2014)
Abstract
Background and Objectives: bisphenol A and nonylphenol are xenoestrogen materials used as a monomer of plastics in widely volume in the production of plastic materials especially mineral water bottles and disposable plastic containers. In this study, we investigated the potential of migration of bisphenol A and nonylphenol from disposable plastic containers into water at different temperatures and also from mineral water into water at different temperatures. Materials and Methods: We conducted bisphenol A and nonylphenol extraction from each sample through liquid-liquid extraction. For identification and quantitative determination of bisphnol A and nonylphenol, we used gas chromatography equipped with mass detector, and for quantitative determination of these two compounds, we used high-performance liquid chromatography equipped with fluorescence detector. Results: We found that increasing temperature increased significantly the rate of migration of these two compounds in the water. Moreover, it was revealed that only the presence of bisphenol A in water of mineral water bottles was detected and the increase in temperature also increases the rate of migration bisphenol A into water. Conclusion: In general, results of this study showed that improper storage of mineral water bottles and also use of disposable plastic containers for hot drinks would result in increasing consumer exposure to these compounds.
Kh Ghattavi, A Naji, S Kord,
Volume 12, Issue 1 (5-2019)
Abstract
Background and Objective: Marine pollution is growing due to human activities. Continuous increase in plastic production and poor management of plastic waste resulted in a significant increase of this contaminant in aquatic environments. This in turn led to the widespread presence of Microplastics (MPs) with a size of less than 5mm.
Materials and Methods: In this study, frequency, distribution, color and type of MPs in the gastrointestinal tract of fish in Oman Sea were investigated using random sampling, tissue digestion and flotation of MPs.
Results: The total number of the MPs found in the studied species was variable. The highest number of MPs were found in the species belonged to Rastrelliger kanagurta and Nemipterus japonicus (29%) and Saurida tumbil, Trichiurus lepturus and Paragaleus randalli (14%).
Conclusion: The forms mostly observed were belonged to microfibres (86%), fragment (11%) and pellet (3%). The most frequent colors that were detected were in a decreasing order blue, pink and black. The results demonstrated that the highest concentrations of MPs were observed in Ratrelliger kanagurta and Nemipterus japonicus species. The present study provides useful information for further research, and a background analysis to monitore the pollutants in the Oman Sea.
Kh Ghattavi, A Naji,
Volume 12, Issue 3 (12-2019)
Abstract
Background and Objective: Microplastics (MPs) are well-known emerging contaminants in the marine environment. A key route by which MPs can directly affect marine life is through ingestion.
Materials and Methods: In order to investigate and measure MPs in the Persian Gulf, random sampling and digestion of tissues and flotation of MPs were used. This method has been used to study the frequency, distribution, shape and color of MPs in in the digestive system of fish in the Persian Gulf.
Results: According to the results, the highest concentration of extracted MPs were found in Sillago sihama (62%), Diagramma pictum (26%), Lutjanus johnii (6%), Otolithes ruber (5%), Epinephelus coioides (1%). However, MPs were not observed in Scomberomorus commerson.
Conclusion: The relative contribution of different forms of MPs in any fish showed that microfibers with the most abundant forms of MPs and fragments and films were observed to have the lowest concentration of 11% and 2%, respectively. Based on our results, it is suggested that Sillago sihama is suitable indicator of MPs contamination among studied fish in the Persian Gulf. Ingestion of MPs provides a potential pathway for the transfer of plastic additives, metals, PAHs and other POPs to wildlife and human consumers of fish. Therefore, more comprehensive investigations on MPs and nano-plstics should be conducted in food chain of seafood.
Mina Yeganeh Far, Ata Shakeri, Meisam Rastegari Mehr, Omid Lahijani,
Volume 13, Issue 1 (4-2020)
Abstract
Background and Objective: Microplastics (MPs) pollution are considered as a major growing global environmental problem in the past few decades. Dams could be an important reservoir for microplastics accumulation, therefore, in this study the presence of microplastics in sediments of Taleqan Dam and its upstream river was investigated in order to: 1) determine the local status of microplastic pollution and 2) determine the abundance and characteristics of the identified microplastics.
Materials and Methods: Sediment sampling was performed at 15 stations in the upstream of the river and the dam reservoir. After the sample preparation, separation method based on density difference was used for separation of the microplastics from the sediment, and stereo microscope and SEM-EDX were used for counting microplastics and investigation of their characteristics.
Results: Based on the results, maximum of the counted microplastic particles were observed in Taleqan City area with 2050 particles/300 g and minimum number was observed in the dam reservoir with 478 particles/300 g of sediment. The dominant shape, color, and size of the counted particles were polyhedral, colorless (transparent), and 100-250 μm, respectively.
Conclusion: The results showed that the concentration of microplastics in the stations near the urban and rural areas were higher due to the entry of sewage and the release of municipal solid wastes. Also, their concentrations were high in the stations close to the dock area of the dam due to the greater traffic of the locals and tourists and dumping of wastes in the shoreline of the lake.
Hamze Sharifi, Hossein Movahedian Attar,
Volume 14, Issue 1 (5-2021)
Abstract
Background and Objective: Recently, microplastics (MPs) have been found in the aquatic and terrestrial environments, air, and food. Other pollutants can be transported by MPs and pose a threat to the human, animal, and environment. Measurement and evaluation of microplastics can either increase knowledge about them or boost understanding of their possible harmful effects. However, no standard method has been established to measure microplastics and the measurement of microplastics has been done by various methods in different published studies. The aim of current study was to investigate different methods of measuring microplastics in water and wastewater environment and identifying the strengths and weaknesses of these methods.
Materials and Methods: The present review study was conducted during the winter 2021, by searching the papers cited in PubMed, Google Scholar, Web of Science, and Scopus databases using the keywords "Microplastic", "Water", "Drinking-water", "Wastewater", "Surface", "Bottled-water" and "Marine" and selecting articles published between 2015 and 2021 in reputable journals.
Results: The main stages of MPs measuring in various studies included sampling and sieving, pretreatment and digestion, density separation, counting and Identification of MPs by their chemical composition.
Conclusion: Digestion using H2O2, density separation using NaCl, counting by stereomicroscope, and Spectroscopy using FTIR and micro-RAMAN are the most widely used methods in the studies related to detecting MPs in water and wastewater environment. However, different methods of measuring and identifying microplastics have made comparing the results of studies difficult and it seems that efforts should be made to standardize these methods.
Fatemeh Tabatabaei, Roya Mafigholami, Hamid Moghimi, Sanaz Khoramipour,
Volume 15, Issue 1 (4-2022)
Abstract
Background and Objective: Microplastics can have harmful effects on living things, including humans. These particles have been identified in all water, soil, and food sources. Among these, freshwater resources are more important, because they are considered a water source for humans through drinking water treatment plants (DWTPs). Therefore, this study investigates the performance of Tehran DWTPs in removing these particles.
Materials and Methods: In this study, the performance of three DWTPs in Tehran in removing these particles was investigated. In most studies worldwide, particles larger than 1 µm were examined, but in this study, nanoplastic particles smaller than 1 µm, as well as the effect of the warm and cold seasons of the year on the concentration of these particles were also examined.
Results: According to the results of the study, the amount of micro and nanoplastic particles at the inlet of treatment plants in the warm season of the year was 2569 ± 309 to 3918 ± 425 MP/L, and the output was 1492 ± 32 to 2279 ± 146 MP/L, which indicates an increase in these particles in the warm season. As a result, the studied treatment plants were only able to remove 32.1 to 59.9% of these particles. In addition, using electron microscopy, MPs were classified into three categories in terms of appearance: fiber, fragment, and film. This study completes the knowledge of MPs in this area.
Conclusion: Based on the results of this study, Tehran DWTPs have poor performance in removing these particles.
Mohamad Mehdi Ghorbaninejad Fard Shirazi, Sakine Shekoohiyan, Gholamreza Moussavi, Mohsen Heidari,
Volume 15, Issue 1 (4-2022)
Abstract
Background and Objective: Among the emerging contaminants, microplastics threaten public health. This study aimed to determine microplastic and mesoplastics in soil of residential areas adjacent to Tehran Landfill and assess its ecological risk.
Materials and Methods: The present descriptive cross-sectional study was conducted on 20 shallow and deep soil samples from residential areas near the Tehran landfill in July 2021. The microplastics were floated in NaCl and ZnCl2 solutions, and the mesoplastics were separated manually. The identification of physical and chemical properties of polymers was performed by stereomicroscope and FTIR analysis, respectively.
Results: The average amount of micro-plastics in shallow and deep soils estimated 76±34.98 and 24.7±19.79 particles/kgsoil, respectively. The average amount of mesoplastics obtained 5.25±2.91 and 3.55±1.09 particles/kgsoil, in shallow and deep soils, respectively. Paired-samples T-test showed significant differences between shallow and deep soil in terms of plastic particles (p<0.001). The most abundant microplastic particles were the fragment-shaped with the particle size of 0.1-0.5 mm and LDPE polymer types with the percentage of 37.75, 44.64, and 46.15, respectively. Mesoplastic particles, the 0.5-1 cm film-shaped particles and LDPE polymer types with the percentage of 62.76, 61.46, and 50.7 were found as the most prevalent. Microplastics and mesoplastics' potential ecological risks value in all sampling points was less than 150, indicating low ecological risk.
Conclusion: Despite the low PERI of microplastics and soil mesoplastics in residential areas, the Eri index for LDPE was high. Thus, Ecological risk is probable if control measures are not taken against plastic pollution.
Mahdieh Jafari, Abolfazl Naji, Moslem Sharifinia, Moslem Daliri,
Volume 15, Issue 4 (3-2023)
Abstract
Background and Objective: Microplastics enter the food chain of aquatic animals; they cause damage to the digestive system, disruption of the reproductive cycle, and finally their death. The present study was conducted to investigate the microplastic pollution in the digestive system of Vanami shrimps cultivated in some shrimp farms in Bushehr, Khuzestan, and Hormozgan provinces.
Materials and Methods: Sampling was done from two shrimp farms in each port including Bandar Rig in Bushehr province, Bandar Choebdeh in Khuzestan province, and South Tiab located in Hormozgan province. 90 shrimp samples were randomly collected from each breeding farm from June to October 2019. The identification method of microplastics was done by FT-IR spectrophotometer.
Results: The highest frequency of microplastics related to farmed shrimps was 41.11% in the fields of Khuzestan province, and a lower amount of microplastic pollution was observed in Hormozgan and Bushehr provinces with 28.88% and 17.70%, respectively. According to one-way ANOVA, the mean of microplastics in the digestive tract of shrimp had a significant difference in the studied stations (p<0.05). The most type and colors of microplastics in the digestive system of shrimps in the farms of all provinces belonged to fiber and black color. Polypropylene and polystyrene were detected in microplastics found in the digestive system of shrimps.
Conclusion: Microplastics were observed in some of digestive tracts of the shrimps of the breeding farms examined in this research in all three provinces of Bushehr, Khuzestan, and Hormozgan. The highest frequency of microplastics in the digestive tract of shrimps is related to the breeding farms of Khuzestan province, and Hormozgan and Bushehr respectively have a lower amount.
Sanaz Ghaffari, Alireza Riyahi Bakhtiari, Seyed Mahmoud Ghasempouri, Ali Nasrolahi,
Volume 16, Issue 3 (12-2023)
Abstract
Background and Objective: Today, cigarette butts have become one of the most significant forms of waste. This study aims to assess the level of cigarette butts pollution along the Guilan coasts and explore the factors influencing their distribution. Additionally, this study discusses experiences and management options related to this issue.
Materials and Methods: In this study, we implemented a standard sampling method adapted from the "NOAA Marine Debris Program" to collect samples from eight beaches. Each station yielded 18 square quadrant measuring 1 × 1 m2. We estimated the severity of cigarette butt pollution along the Iranian coastline and conducted a review of published articles on the harmful effects of cigarette butts.
Results: The density of cigarette butts ranged from 0.22 to 2.11 items/m2. Bojagh National Park showed the lowest contamination of cigarette butts, while Bandar Anzali exhibited the highest. The results indicate an increase in cigarette butt pollution on beaches in densely populated cities compared to less developed coastal areas. Moreover, stations corresponding to tourist beaches and coasts with gentle slopes have a higher potential for cigarette butt accumulation. The level of cigarette butts pollution along the coasts of Bandar Anzali may be attributed to the extensive tourism activities on these beaches.
Conclusion: Given the high level of cigarette butt pollution on crowded coasts, it is imperative to identify beaches with a higher potential for waste accumulation and implement plans for coastal waste cleanup. Furthermore, effective management programs should be developed to promote cultural awareness and reduce cigarette butt contamination.
Lieli Amirkia, Arash Shakouri,
Volume 16, Issue 4 (3-2024)
Abstract
Background and Objective: Microplastic pollution due to its small size can be used by a wide range of marine organisms and accumulate mainly in their digestive system, as they have been found in the tissues of aquatic animals, including fish. Due to the nutritional importance of fish for humans, it is very important to check their contamination. The main purpose of this research is to investigate the presence of microplastics in skipjack tuna (Katsuwonus pelamis) in the Oman Sea.
Materials and Methods: 17 pieces of skipjack tuna were used. After the biometry, dissection and isolation of the digestive system of the fish, the digestion and extraction of microplastics were done using KOH solution. Identification and counting were also done by a stereomicroscope equipped with a digital camera. FTIR spectrophotometric analyses were performed to investigate the polymers.
Results: The total frequency and average frequency of microplastics are 331 particles and 19.4±7.3 particles per individual, respectively. String (64.35%) and pieces (28.7%) were the dominant forms in the samples. The highest color spectrum was assigned to red (28.7%) and the lowest to violet (1.51%). The largest number of identified microplastics had a size of 0.5-1 mm (53%). Analysis of particles by ATR-FTIR method showed that nylon polymer and polycarbonate were the dominant polymer particles.
Conclusion: Microplastics are present in all samples. The abundance of microplastics in water, sediments and contaminated bait makes them easily available and swallowed by fish, which is most likely the main reason for the presence of microplastics in fish.
Zahra Khodarahmi, Sakine Shekoohiyan, Mohsen Heidari,
Volume 16, Issue 4 (3-2024)
Abstract
Background and Objective: Given the concern about the presence of microplastics in the air and settled dust, and the lack of a standard approach for their detection, it is necessary to investigate the methods and techniques used to study this type of pollution in Iran. Therefore, this study aimed to systematically review the methods and techniques used for sampling, quantification, and characterization of microplastics in the air and settled dust in indoor and outdoor environments in Iran.
Materials and Methods: In this systematic review, the keywords Microplastic*, Air*, Atmosphere*, Dust, Indoor, Outdoor, Iran, and their corresponding Persian equivalents were searched until Dec 1, 2023, in Scopus, PubMed, Web of Science, Google Scholar, Magiran, and SID databases. Obtained articles from the databases were analyzed in order to find the eligible ones.
Results: Overall, 175 articles were found in the initial search, and after removing the duplicates and nonrelevant, 13 eligible articles were included in the study. In most of the studies, the samples were digested with H2O2, and the microplastics were mainly analyzed using a variety of microscopes and µRaman spectroscopy. The abundance of microplastics in the indoor environment was much higher than in the outdoor environment.
Conclusion: The results of this study showed that there is the required equipment for the sampling and analysis of microplastics in air and settled dust in Iran, and these pollutants have been detected in both indoor and outdoor environments.
