Iranian Journal of

Background and Objective: Municipal waste transfer stations (WTS), operate as middle elements in waste collection and transfer to the final disposal site. Besides their benefits in waste transportation cost reduction, WTS can cause negative environmental impacts such as noise, air, and water pollution. Environmental impact assessment is an effective solution to reduce the environmental impacts of WTS. This research was conducted at evaluating the environmental impacts of various options defined for WTS in Tehran using the Rapid Impact AssessmentMatrix (RIAM) analysis method.
Materials and Methods: This descriptive-analytical study was performed to assess the environmental impacts of WTS based on field observation and data collection. Comparing was included four options including: continue the current condition of the WTS, three other alternatives considered to be three other alternatives (WTS in open space with the construction of green space) and transfer in enclosed space and with construction of green space and without it. Finally, using the sustainability model, the stability of the options was also measured.
Results: Based on the obtained results, the fourth option (indoor loading/unloading along with establishment of green spaces in WTS) as the first priority for the Construction of transfer stations among the other options has the highest score (0.079) in terms of sustainability as well as the adverse environmental impacts. However, the current environmental status of Tehran WTS (first option) has the lowest score (-0.213) in terms of sustainability and the most destructive environmental impacts and found to be the last priority in establishment of transfer stations.
Conclusion: Combined use of the RIAM and sustainability model can be a promising and reliable way to evaluate and improve the performance of (WTS).
 

Background and Objective:  one of the major challenges in urban management in human societies is related to the collection, recycling and disposal of solid waste and sewage. Poor waste management causes pollution of water, soil and air. It will have a major impact on public health. The aim of present study was to investigate the current status and select the best options of management of municipal solid waste in Noor city (Mazandaran, Iran) using life cycle assessment (LCA) methodology.
Materials and Methods: This research considered with five scenarios: 1) Recycling, composting and unsanitary landfilling; 2) Recycling, composting and sanitary landfilling; 3) Recycling, incineration and sanitary landfilling; 4) Recycling, composting and anaerobic digestion, incineration, sanitary landfilling; 5) Recycling and unsanitary landfilling. The required data for life cycle assessment inventory were collected through reviewing resources, preparing of questionnaires, completing the questionnaire by staff, and field inspections.The life cycle inventory was approved by the IWM model.
Results: The scenario 5, which is the current situation in the region, had the highest environmental impact in terms of toxic emissions and ecological indicators among all the scenarios. Energy consumption in the scenarios 1 and 5 was higher than the unsanitary landfilling in comparison to the other scenarios. Accordingly, the scenarios 5 and 4 had the most and the least impact on methane gas production.
Conclusion: According to the ecological index, the fourth scenario including recycling, composting and anaerobic digestion, and sanitary landfilling was the best scenario.  Fifth scenario with the highest pollution load was the worst scenario evaluated.

Background and Objective: Petroleum compounds are major contributors to aquatic environmental pollution. In recent years, biological treatments as environmental-friendly and cost-effective techniques have been used alongside the various physico-chemical methods. Microbial cell immobilization in hydrogel carriers has been the focus of researchers due to various advantages such as ease of microbial species control, non-direct exposure of pollutants to the cells, increasing cell resistance during different types of stresses and reusability. The main goals of this study were introduction to electrospraying technique in order to size reduction of alginate beads and comparison of heavy crude oil biodegradation using an isolated strain of Bacillus licheniformis in free and immobilized cells.
Materials and Methods: The oil-degrading strain was isolated from oil-polluted site on Kharg Island. Microbial cells were examined in both free and immobilized systems under different conditions (pH=5,7) and initial crude oil concentration (1500,3500 ppm). Electrospraying technique was used for alginate beads production. Residual crude oil content was analyzed by gas chromatograph and gravimetrically method.
Results: The maximum oil removal (61%) was obtained for the immobilized cells at a concentration of 3500 ppm in neutral medium. Overall, according to the results, after the 14^th day, the biodegradation through the immobilized cells was significantly (p<0.05) higher than the free cells. Moreover, the cell immobilization caused the microorganisms to be more resistant to the harsh environments.
Conclusion: This study showed that the immobilized microbial cell system has a great potential for oil wastewater treatment. The electrospraying technique can be used to overcome to the mass transfer limitations.

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.

Background and Objective:  Arsenic has long been considered as a heavy metal and toxic pollutant due to its potential to harm the human health and the environment. Adsorption is one of the mechanisms for arsenic removal from wastewater. Therefore, the purpose of this research was to investigate the feasibility of synthesized chitosan-zirconium magnetic nano fiber on arsenic adsorption from wastewater and to evaluate its kinetic and isotherm models.
Materials and Methods: Synthesis of nanofibers was performed by electrospinning method and the optimal formulation was determined following the experimental design. Then, kinetics and isotherms of arsenic adsorption on the as synthesized nanofibers were investigated. The prepared nanofiber was characterized using X-ray diffraction (XRD), Field Emission Scanning Electron Microscopes (FESEM), Infrared Fourier Transform (FT-IR) and Vibrational Sampler Magnetic Meter (VSM).
Results: The optimal formulation was obtained: 2.84% chitosan, 0.97% nano-zirconium and 0.94% nano-iron. The adsorption of arsenic on synthetic fibers was found to follow quasi-first-order kinetics and the Freundlich isotherm. Furthermore, the effect of initial concentrations of arsenic, contact time, temperature and pH on arsenic adsorption were surveyed. The optimal condition for nitrate arsenic adsorption was obtained at initial concentration of 70 mg/L, 45 min contact time and at pH 3.
Conclusion: According to the results, the synthesized nanofiber displayed a regular network structure with the distribution of the Zr-nanoparticles in its shape. Also, according to the form of magnetometric analysis, it was found that chitosan-nanosirconium magnetic nanofibers are well magnetized and are free magnetic.  Finally, it can be concluded that the synthesized nanosorbent has a high potential for arsenic removal from industrial effluents.

Background and Objective: Global market growth of reverse osmosis (RO) has led to an increase in annual disposal of membrane wastes. Therefore, evaluation of membrane waste management strategies is important to reduce their adverse environmental impacts. Due to the widespread domestic RO membrane market and their economic considerations, this study aims at investigation the direct recycling methods of RO membranes to extend their life cycles.
Materials and Methods: Academic search engines and citation databases such Scopus and PubMed was used to retrieve relevant papers. Selected documents were analyzed and compared in three aspects of technical, economic and environmental issues. 
Results: Direct recycling of RO is performed with fouling removal and degradation of polyamide layer (PA) using oxidizing agents like KMnO₄ and NaOCl. The degradation rate of the PA layer is controlled by optimizing the oxidant concentration during the oxidation process. Factors such as the type of membrane used, its storage conditions, the operating units’ conditions and the final expected product will determine the required concentration-time values. Strategies to reduce these values are very important from an economic and environmental point of view. Decreasing the concentration of oxidizing agent reduces the chlorinated and halogenated compounds emitted from the oxidizing unit which subsequently lessen their harmful environmental impacts and reduces the energy consumption required for treatment.
Conclusion:  The conversion of RO membranes to porous filters is technically possible by optimizing the conditions. In addition, the proper choice of RO membrane and final product type lead to economic and environmental productivity.

Background and Objective: Improper landfilling of drilling waste has adverse effects on the environment and human health. This study aims to select suitable landfills for oil and gas drilling waste on Qeshm Island using GIS and AHP.
Materials and Methods: In this study, a weighted map was prepared based on each criterion affecting the site location. In the next step, each of the prepared layers was ranked. Higher rating indicated the importance of each layer while lower values corresponded to their insignificane.
Results: The reasults of this study showed that the distance from population centers (weight 0.222), communication network (roads) (weight 0.169) and surface waters (weight 0.142) are important parameters for landfill siting. The combination of ranked maps and the weights obtained from AHP, divided the landfill area to “completely suitable”, “suitable”, “relatively suitable”, “relatively unsuitable” and “unsuitable”.
Conclusion: Priorities identified in “completely suitable” areas can be the basis for decision-making, and appropriate locations can be on the agenda as next priorities.

Background and Objective: Hexavalent chromium is reported to be highly toxic, mutagenic and carcinogenic; hence treatment of water and wastewater contaminated with this element by low-cost and environmentally friendly methods is of great importance. Therefore the aim of present study was to evaluate the efficiency of Fe(II) modified bentonite for hexavalent chromium removal from a simulated wastewater.

Materials and Methods: In this study, Fe(II) modified bentonite was synthesized. Structure and morphology of bentonite were investigated by XRD and SEM techniques. Experiments were carried out as central composite design with three input parameters namely initial hexavalent chromium, pH and adsorbent dosage at 5 levels. Finally, the results were assessed by adsorption isotherm models.
Results: The findings revealed that complete removal efficiency of Cr (VI) achieved at pH of 2, initial hexavalent chromium concentration of 20 mg/L and adsorbent dose of 5 g/L. The adsorption isotherm model found to fit well with Langmuir isotherm model and revealed that the monolayer adsorption of hexavalent chromium at adsorbent surface was happened. The equilibrium data better fitted the Langmuir isotherm model suggested a monolayer adsorption nature of the modified bentonite.
Conclusion:  The findings in this study showed the promise of use of Fe(II) modified bentonite for Cr (VI) removal. Moreover, response surface methodology can be used as an effective method to optimize hexavalent chromium removal from wastewaters. 

Background and Objective: Considering the importance of alkalinity in pH regulation and its buffering role, in this study, the effect of inlet wastewater alkalinity on the efficiency of the anaerobic unit of the wastewater treatment plant. Moreover, a superior chemical compound in providing alkalinity to wastewater was investigated.
Materials and Methods: This study was performed in the treatment plant to determine the relationship between input alkalinity and removal efficiencies of COD, BOD₅ and TSS. In order to determine the optimal alkali material for superb anaerobic wastewater performance, four common chemical substances including, NaOH, Na₂CO₃, Ca(OH)₂ and MgO were selected and examined using One Factor At Time (OFAT) test method.
Results: According to the results maximum removal efficiencies were obtained 62, 66.6 and 71.2% for COD, BOD₅ and TSS, respectively under alkaline condition of 1260 mg/L CaCO₃. Furthemore, the optimal dose to supply one unit of alkalinity by Na₂CO₃, Ca(OH)₂ and MgO were 0.53, 0.54 and 0.3 mg/L, respectively. These values were obtained 5 min contact time and mixing rate of 150 rpm. However, for NaOH the optimal dose supply was obtained 0.35 mg/L for 3 min contact time and mixing rate of 100 rpm.
Conclusion: In conclusion, the performance of anaerobic baffled reactor is highly related to the supply of influent alkalinity to the reactor. In addition, the use of MgO can be considered as a suitable alkaline substance to neutralize acidic wastewater and provide alkalinity for ABR system.

Background and Objective: Pesticides are the major components of production in modern agriculture, however, as their widely usage, the hazards associated with their wastes have become of increasing concern. The aim of this study is to investigate orchard farmers’ attitudes toward proper disposal of pesticide wastes.
Materials and Methods: The statistical population of the study includes all orchard farmers in Meshkinshahr County (N=32,300). A total sample size of 300 farmers was selected and the data were collected. The research instrument was a questionnaire which was validated by a panel of university staff. A pilot study was conducted with 30 farmers outside the sample villages and Cronbach's alpha showed high reliability of the instrument.
Results: Due to the pesticides use, significant amounts of wastes are produced annually. Farmers do not properly dispose pesticide wastes. They leave the wastes on the farm, dump it in canals or river flow, or burn it. Farmers were not well informed about triple rinsing of containers before disposal. Most farmers used masks, hats, and gloves, 53% used boots and 7.7% used goggles, though none of them used coverall during pesticides’ handling. Respondents took negative to moderate attitudes towards proper wastes disposal. Age, education, and participation in extension programs were the most important determinants of the attitudes.
Conclusion: Considering the relatively negative attitude and improper waste disposal, it is necessary to establish centers for waste collection, to inform and encourage farmers to dispose of waste properly. Relevant organizations, such as health and the environment should plan for pesticide waste management.

Background and Objective: Since industrial waste management requires accurate knowledge of quantity and quality of solid wastes, this study was conducted to assess quantitative and qualitative characterization of industrial solid waste in Qazvin province, Iran and investigate its related pattern management.
Materials and Methods: Based on the guideline of Iranian Environment Protection Organization, industries were classified into 10 groups. Then according to the abundance of industries in each group, 276 industries and 4 wastewater treatment plants were selected. The Basel Convention criterion was used to identify special solid wastes. Quantitative and qualitative characteristics and management pattern of industrial wastes were determined by referring to the industries and completing a researcher-made questionnaire.
Results: The total types of identified industrial solid wastes were 1726. According to the guideline of Basel Convention, 33.7% of identified wastes were classified as special wastes. The total amount of solid wastes was 38826 ton/month. The maximum solid wastes production was in the chemical industries with 14,380 ton/month. The recovery and recycling rates were 8.96 and 6.44%, respectively, and 36.44 % of industrial waste was sold directly.
Conclusion: The results of the study showed that the management of industrial solid wastes in Qazvin province does not follow a specific pattern. In addition, the quantity and the composition of solid wastes in the study area is a serious potential for environmental pollution and threatening human health. Therefore, it is necessary to establish a center responsible for industrial wastes management and design a centralized industrial waste disposal system.

Background and Objective: Nowadays, the development of green entrepreneurship plays an important role in sustainable employment, reducing environmental issues, economic development, and moving towards sustainable development. Thus, the present study has been carried out aiming to identify and analyze the factors facilitating the green entrepreneurship process in the field of urban waste using a mixed (quantitative-qualitative) method.
Materials and Methods: The present study was carried out with a mixed approach (exploration projects). For this purpose, using theoretical sampling logic, 14 experts were selected by snowball technique and the required data were collected through semi-structured in-depth interviews to achieve theoretical saturation. In the quantitative section, data were collected through interaction questionnaires handed out to 26 experts who were selected through purposive sampling, and the integrated DEMATEL-ISM technique was employed to build a regular hierarchical structure.
Results: Layer-by-layer model was displayed in 4 levels using DEMATEL-ISM technique. The first layer consists of improving laws and regulations and designing a suitable landscape as the most infrastructural, the second layer includes improving infrastructure issues, expanding supportive issues, culturalization and increasing public awareness, the third layer includes exploiting the potentials of the region and attracting private sector participation, and the fourth layer comprises of entrepreneurial management.
Conclusion: The results show that the first step in creating a facilitator environment for green entrepreneurship process in the field of urban waste is to improve the macro structures that should be facilitated mainly by the central government, the second step is related to the proper infrastructure and preparation of public space governing the society. In the third step, it was found that the development and utilization of the region’s potential increases its operational effectiveness. Finally, with entrepreneurial management, all activities that occurred at previous levels can be used effectively.

Background and Objective: Limited water resources in arid and semi-arid regions are one of the major limiting factors in agricultural production. Thus, unconventional water resources, such as urban treated wastewater, may be used for irrigation. Application of wastewater to the soil may cause accumulation of heavy metals (HMs). Soil pollution causes uptake of these metals by plants and their entrance to the food chain. In the present greenhouse research, concentration variations of HMs (lead (Pb) and cadmium (Cd)( in soil and sweet pepper (Capsicum annuum) plant were investigated.
Materials and Methods: The experiment was conducted as a completely randomized design with three replications and irrigation with different wastewater treated (well water, wastewater treatment and diluted wastewater). To evaluate the effects of different irrigation treatments on soil, parameters of acidity (pH), electrical conductivity (EC), the concentration of heavy metals Pb and Cd in soil were studied.  Additionally, for the effects of irrigation treatments on sweet pepper plant, parameters of biomass weight, fresh and dry weight and Pb and Cd concentrations (in branches, fruits and roots) were measured. The amount of Pb and Cd in the pepper were measured by ICP-OES. The obtained average concentrations were compared using one-way analysis of variance (ANOVA), and the Duncan test was used to determine the differences between groups (p <0.05). The independent t-test was also used to investigate the difference in concentrations of Pb and Cd in soil and water (p <0.05).
Results: The results of chemical analysis of soil and pepper showed that irrigation with wastewater did not cause a significant increase in the concentration of Pb and Cd in the soil and in the branches, fruits and roots of the pepper. The concentration of Pb and Cd in the soil and in the branches, fruits and roots of the pepper was within the allowable and standard concentration range. The difference in lead and cadmium concentrations in the soil before planting was not significant; however, at the end of the study period, the Pb concentration in pepper was higher than the Cd concentration. The use of wastewater increased the fresh and dry weight of branches, fruits and roots of the pepper.
Conclusion: The results showed that Pb and Cd concentration in roots and aerial parts of pepper plant was not increased significantly as a result of wastewater irrigation (p <0.05). The results of this study are limited to one growing season and by the continued use of municipal wastewater, the concentration of Pb and Cd in the soil and then in the plant may exceed the standard. Especially in the case of Pb, which seems to have shown a slight tendency to increase relative to the primary soil and the pepper. Therefore, the continuation of this study is recommended to evaluate the long-term effects of Bushehr municipal treated wastewater on the concentration of heavy elements in soil and plants, and soil properties. Overall, it should be acknowledged that based on technical recommendations, the use of treated wastewater are not recommended.

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.

Background and Objective: Hydrolysis of fat, oil and grease by ultrasonic waves is a pre-treatment method before anaerobic digestion which can change their physical, chemical and biological properties. The main purpose of this study was to investigate the efficiency of ultrasonic waves to improve the hydrolysis process and its use as an auxiliary substrate to increase the efficiency of anaerobic digestion process along with municipal sewage sludge.
Materials and Methods: Sampling of fat and oil of the degreasing unit and physical preparation by conducting ultrasonic waves with frequencies of 20 kHz and current density of 0.012-0.14 W/mL within 0-12 min were performed. The efficiency of pretreatment process were performed through tests such as soluble chemical oxygen demand (SCOD), and lipase enzyme activity. In addition, the anaerobic digestion process were evaluated by measuring the TS, VS, VA (volatile acidity), alkalinity, biogas production and biogas methane content.
Results: The results showed that the highest increase in the activity of lipase enzyme under ultrasonic effect with a power of 0.1 w/mL was obtained after 8 minutes. Organic loading with 10%, 20% and 40% FOG/MSS ratios: resulted in 55%, 66% and 64% increase in methane production compared to the control samples, respectively. Organic loading over the 40% FOG/MSS caused a limitation in the simultaneous digestion process.
Conclusion: The results show that ultrasonic wave pretreatment with optimal power and time can improve the hydrolysis of TFOG while increasing the activity of lipase enzyme and also its use as an auxiliary substrate can enhance digestion performance and make digestion more stable.

Background and Objective: Due to the increasing trend of municipal solid waste (MSW) production, if a suitable management system is not applied, it will lead to environmental pollution and endanger human health. The aim of this study was to compare different scenarios of waste management in Chalous city with life cycle assessment (LCA) approach and to select the most efficient method in terms of environmental adaptation.
Materials and Methods: After investigation of the quantitative and qualitative characterization of the produced wastes and the current waste disposal method in Chalous city, the obtained results were used to evaluate the life cycle of six different waste management scenarios; including the combination of four methods of composting, recycling, incineration along with energy extraction and sanitary landfilling. Emissions from various scenarios were assessed using IWM-2 model.
Results: The current system of municipal waste management in Chalus (scenario 1) with ecological index of 1.73+06 poses the highest pollution load into the environment. The inclusion of compost disposal methods in the organic waste sector and recycling of biodegradable materials significantly reduces the emissions of environmental pollutants by increasing the amount of materials for recycling and reuse, as well as preventing emissions from raw material production. The fifth scenario (60% compost, 30% recycling and 10% sanitary landfill) with ecological index of -2.00+05 was known as the lowest contamination scenario.
Conclusion: Considering that a high percentage of Chalous municipal solid waste composition is perishable materials (organic waste), simultaneous application of composting and recycling methods can be a suitable option for optimal management of wastes in Chalous city and play an important role in reducing the environmental pollution load.

Background and Objective: Antibiotics are hardly decomposable and resistant contaminants in the environment that according to their anti-biological properties, it is necessary to eliminate or reduce the amount of them before entering the environment. Therefore, the main goal of this research is to investigate the Fenton and Fenton-like process efficiency for the treatment of wastewater containing Spiramycin antibiotic.
Materials and Methods: The effect of independent variables including pH, contact time, oxidant concentration (H₂O₂), and catalyst concentration (Fe²⁺ and Fe³⁺) on the COD removal efficiency were measured using COD meter. The ranges and number of experiments were assigned by RSM (Response surface method) using design expert software.
Results: The optimum conditions of Fenton process with treatment efficiency of 63.31% were obtained at pH 4, hydrogen peroxide concentration of 50 mg/L, Fe²⁺ concentration of 75 mg/L and contact time of 5 min. The optimum conditions of Fenton-like process with treatment efficiency of 51.21% were obtained at pH 3, hydrogen peroxide concentration of 60 mg/L, Fe³⁺ concentration of 137.5 mg/L and contact time of 32.5 min. Based on the ANOVA analysis results, the f value in Fenton method indicates that the model is significant.
Conclusion: According to the results, Fenton oxidation process was selected as the optimum method to remove COD from synthetic wastewater containing Spiramycin antibiotic which may be applied as an efficient method for the treatment of wastewaters containing antibiotic.