Samira Abduolrahimi; Ali Akbar Safari Sinegani
Abstract
Background and purpose: Municipal and hospital waste land fills that have various contaminants, especially pharmaceuticals, provide a suitable habitat for resistant bacteria which play a special role in the transfer of resistance genes. Therefore, the abundance of microorganisms and the antibiotic resistance ...
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Background and purpose: Municipal and hospital waste land fills that have various contaminants, especially pharmaceuticals, provide a suitable habitat for resistant bacteria which play a special role in the transfer of resistance genes. Therefore, the abundance of microorganisms and the antibiotic resistance of bacteria in soil and leachate samples of municipal and hospital waste burial sites in Hamedan city were investigated.Materials and methods: The characteristics of soil and leachate as well as the abundance of their microorganisms were tested and counted. Also, the percentage of bacteria resistant to ten commonly used antibiotics ampicillin, amoxicillin, cefixime, gentamicin, streptomycin, tetracycline, doxycycline, chloramphenicol, lincomycin and metronidazole was investigated. In addition, the response of bacteria from two virgin soils and new rubbish landfill to different concentrations of three antibiotics, ampicillin, gentamicin and tetracycline, were measured.Results: The log of population of fungi, actinomycetes, pseudomonas, and enterobacters, was the highest in new rubbish landfill. They were 5.35, 5.28, 6.13, and 5.98 respectively. The percentage of bacteria resistant to all ten antibiotics was higher in samples of new rubbish landfill than in other locations and lower in virgin soil than in other locations. These results were also seen in the dose response of ampicillin, gentamicin and tetracycline antibiotics. The inhibitory concentrations of these antibiotics for new rubbish landfill bacteria were 1500, 1000 and 100 mg/l, respectively. But for virgin soil, they were much less (10, 18 and 50 mg/l respectively).Conclusion: In general, this research showed that municipal and hospital waste landfills provide a suitable habitat for antibiotic-resistant bacteria, which may increase the transfer of resistant genes among soil native bacteria. Therefore, the bacteria that reach the soil through waste can be more harmful.
Samira Abduolrahimi; Ali Akbar Safari Sinegani
Abstract
Background and Purpose: The biological pollution of landfill sites for urban waste is a crucial concern. This study aims to investigate the resistance of bacteria in contaminated soils at waste burial sites against heavy metals in Hamadan.Materials and methods: The physical and chemical characteristics ...
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Background and Purpose: The biological pollution of landfill sites for urban waste is a crucial concern. This study aims to investigate the resistance of bacteria in contaminated soils at waste burial sites against heavy metals in Hamadan.Materials and methods: The physical and chemical characteristics of soils were examined, and the total amounts of metals such as copper, lead, zinc, and cadmium were measured. Additionally, pollution load index (PLI), average pollution index (PIavg), and pollution degree (Cdeg) were estimated and analyzed. Furthermore, the percentage of stable bacteria resistant to copper, lead, cadmium, and zinc in the NA culture medium was studied by measuring the logarithm of microorganism abundanceResults: Among the mentioned sites, the soil surrounding the leachate lagoon exhibited the highest levels of organic carbon, available phosphorus, and potassium. The PLI and PIavg indices for virgin soil were below one, indicating that this soil was not polluted. However, these indices were above one for the other five sites, indicating pollution. The intensity of soil pollution in these sites exceeded the permissible limit. The logarithm of population for fungi, actinomycetes, pseudomonas, and enterobacters was highest in the new rubbish landfill, with values of 5.35, 5.28, 6.13, and 5.98, respectively. The percentage of bacteria resistant to lead was 100% in all sampled soils, but in the leachate, it was lower than 64%.Conclusion: Overall, the percentages of bacteria resistant to copper, zinc, and cadmium in the new rubbish landfill site were higher compared to other sites, which may be attributed to the landfilling of urban waste in the soil.
Reza Peykanpour Fard; Saeid Pourmanafi; Mohammad Erfan Kaghazchi
Abstract
Background and purpose: In recent years, the rapid growth of cities has been led to an increase in the production of various types of solid wastes in urban areas. Although landfilling is the last step in municipal solid waste management, but it is one of the common methods in developing countries’ ...
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Background and purpose: In recent years, the rapid growth of cities has been led to an increase in the production of various types of solid wastes in urban areas. Although landfilling is the last step in municipal solid waste management, but it is one of the common methods in developing countries’ municipal solid waste management. The purpose of this study is to accurately locate urban landfills in Naien county by using a combination of fuzzy and boolean methods. Materials and methods: In this study, AHP model was used to standardize and determine the weight of criteria and sub-criteria. The innovation of this research is the combination of the results of fuzzy and boolean logic. The fuzzy method consists of two groups, the first group is calculation the weight of criteria and the other one by calculating the weight of sub-criteria, and the results of boolean logic with five classes including calculation the weight of criteria and sub-criteria. Results: The results of this study show that the mentioned fuzzy and boolean methods have identified 34, 48779, 16000 and 7630 hectares of areas in Nain county as the most suitable areas for creating urban landfills. According to the weight of methods, a single map with four main patches is resulted by combination of these four methods, which includes a total of 5055 hectares in Nain. Conclusion: The results of this study show that the combination of fuzzy and boolean logic results provides better areas for landfill than using the methods individually.
Shahram Sadeghi; Behzad Shahmoradi; Nammam Ali Azadi; Kazhal Karami; Mona Ghaslani; Mona Karami Cheshmeh Zangi; Bayan Hossienzadeh
Abstract
Background and Aim: One of the main resources of methane emissions is waste disposal buried in landfill sites. To control the negative effects of methane emission on Ozone layer known as greenhouse effect, the routine is to capture methane and use it as an energy resource. The objective of this study ...
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Background and Aim: One of the main resources of methane emissions is waste disposal buried in landfill sites. To control the negative effects of methane emission on Ozone layer known as greenhouse effect, the routine is to capture methane and use it as an energy resource. The objective of this study was to assess the quantitative and qualitative characteristics of the Saqqez municipal solid wastes and to estimate the potential methane gas emission from the city’s landfills using LandGEM software over 2015-2034. Materials and methods: In this descriptive cross-sectional study, the amount of solid wastes, the population of Saqqez city, and the characteristics of municipal solid waste landfills were used to estimate the methane gas emission using LandGEM software. Initial population and the population growth of Saqqez were obtained from the last census of 2012. Results: The amount of annual waste was 62050 tons with methane emissions of 32m3/h in 2016. It is estimated that this amount to increase to 108805 tons with methane emissions of 2203m3/h in 2034. Conclusion: In summary, the results of this study can assist city managers to prepare the appropriate actions to control and manage methane emissions to reduce its negative effects especially on environment.
Mohammad Hadi Abolhasani; Ehsan Rezai
Abstract
Background and Objectives: The solid waste in landfill is transformed into landfill gas during a biochemical conversion process called bio-degradation. Landfill gas is a product of waste decomposition containing 40 to 60 percent of methane and various amounts of other gases. The present project aims ...
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Background and Objectives: The solid waste in landfill is transformed into landfill gas during a biochemical conversion process called bio-degradation. Landfill gas is a product of waste decomposition containing 40 to 60 percent of methane and various amounts of other gases. The present project aims to estimate the proportion of environmental gases of Landfill No. 1 in Shahin Shahr (total landfill gas, methane gas and carbon dioxide gas), compare gas emissions over a 30 year period, and assess the capacity of the landfill for energy extraction. Material and Methods: The field of research was Landfill No. 1 at Shahin Shahr Recycling Plant (Isfahan) located in Ja’farabad Mountains, whose capacity was completed in 2010 and landfill gas assessment was carried out. The total amount of produced gases including methane and carbon dioxide was calculated using the first-order degradation model over a 30 year period. The proportions of these gases in Landfill were calculated from 2013 to 2043. Result:The results show that the amount of landfill gases production declined over the time. The maximum production of methane and carbon dioxide was about 350 and 950 thousand kilograms in 2013 and the minimum production of methane and carbon dioxide is estimated about 57 and 157 thousand kilograms, respectively, in 2043. The total volume of gases produced in this landfill has been estimated to be about 15 million cubic meters in 30 years, of which 27 percent is methane and 73 percent is carbon dioxide. The amount of methane and carbon dioxide gas is estimated to be about 5 million and 13 million kilograms in 30 years, respectivel. Conclusion:Generally, the landfill gases production declined over the time. It is recommended to use energy recovery technologies for controlling greenhouse gas emissions and generation of required energy for the ShahinShahr recycling plant in order to use this volume of gas.
HOSEIN ALIDADI; Ali Asghar Najafpoor; somayeh etemadi mashhadi; Batoul Mohebrad; aliakbar dehghan
Abstract
Introduction: Waste leachate contains hazardous organic compounds such as nitrogen compounds and high concentrations of poisonous compounds; the remediation of these pollutants from the environment is considered as a global problem. These pollutants make serious environmental problems through their penetration ...
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Introduction: Waste leachate contains hazardous organic compounds such as nitrogen compounds and high concentrations of poisonous compounds; the remediation of these pollutants from the environment is considered as a global problem. These pollutants make serious environmental problems through their penetration into groundwater and bioaccumulation. Therefore, leachate treatment is essential with suitable and appropriate methods. Anaerobic digestion is considered as one of the most cost-effective methods for this mean. This study aimed to evaluate the efficiency of an anaerobic digester in simultaneous removal of chemical oxygen demand (COD) and TKN from landfill leachate during the process of anaerobic co-digestion for landfill leachate and fresh cow dung. Materials and Methods: In this study, landfill leachate of Mashhad and cow dung was mixed in 3/1, 1/1 and 1/3 ratios. These treatments were exposed under anaerobic digestion with same conditions such as environmental temperature. COD and TKN were measured at the beginning and the end of the process. Results: In the control treatment, COD decreased about 5% and the reduction of TKN was 9.09%. Whilst COD reduction was about 65%, 75%, and 70% in the treatments of 3/1, 1/1 and 1/3 Ratio respectively. Also, TKN decreased 33.26, 82.16 and 84.73% in the 3/1, 1/1 and 1/3 Ratio correspondingly. Conclusion: The results of this study indicated that the applied method is an efficient and economical approach for elimination of COD and TKN from waste leachate. Because it not only is considered as an environmentally friendly method for this regard, but also it will also make economic benefits from methane production.
Mohsen Azizi; Abbas Khashei; Mehdi Dastorani
Abstract
Background & objective: Today, the pollution caused by landfills is considered as one the serious environmental threats, including groundwater resources. The purpose of this research, the use of mathematical models and numerical with high precision in determining and explaining the current situation ...
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Background & objective: Today, the pollution caused by landfills is considered as one the serious environmental threats, including groundwater resources. The purpose of this research, the use of mathematical models and numerical with high precision in determining and explaining the current situation and relatively accurate predictions, to examine the groundwater pollution caused by leakage of leachate centers around landfill. Materials & Methods: In this research, The MODFLOW, MODPATH and MT3DMS models was used to estimate the speed of movement of pollution, tracing path and simulate the process of transfer of leachate producedat San Angelo landfill site in the United States to the downstream drinking water well. Also Three scenarios of a) improved bedding of landfill bottom and reduced leachate penetration to 25%; b) Reducing the amount of extraction downstream drinking water well to 20%; c) landfill Movement as much as 100m to upstream were evaluated. Results: The results of the modeling showed that in the current situation, the leachate produced landfill reaches the downstream well going through a distance of 608 meters in 2158 days. By applying three scenarios in the numerical model was seen that the leachate reaches to the downstream well by passing a distance of 613, 618, and 667 m in 4000, 3250 and 4000 days, respectively. Conclusion: Therefore, in the field of locating the landfill and leakage of leachateto groundwater, numerical models can be used to predict the direction and speed of pollution movement and to make management decisions for reducing the time and distance of arriving the pollution at the groundwater.
Neda Fazelnejad; Rouhollah Mirzaei; Rasool Heidari
Abstract
Introduction: Nowadays, increasing the urban population, followed increasing in waste production has attracted the attention of environmental researchers towards the sanitary waste disposal. It is estimated that in Khorramabad city with a population of over than 348,216 people, about 458 tones of urban ...
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Introduction: Nowadays, increasing the urban population, followed increasing in waste production has attracted the attention of environmental researchers towards the sanitary waste disposal. It is estimated that in Khorramabad city with a population of over than 348,216 people, about 458 tones of urban waste are daily produced which are dumped in open lands. Therefore, finding a suitable site for waste disposal is necessary. The purpose of this study is to identify and introduce suitable locations for the sanitary waste disposal across the city using Electre as a Multi Criteria Decision Analysis. Material and methods: For this purpose, 14 criteria including soil erosion, geology, land use, distance to roads, distance to rivers, springs and kanats, distance to faults, distance to cities and villages, slope, elevation, groundwater depth, distance to protected areas and climate were used. Three common methods including Boolean, Analytic Hierarchy Process (AHP) and Linear Combination Weighted (WLC) were used to combine the criteria maps. Considering the minimum area required for landfill sitting for a period of 20 years, five candidate sites were ultimately extracted from the final resulting map of WLC in order to introduce the best site for urban landfill. Then, these five candidates were ranked using Electre model. Results: Results of weighting process showed that the groundwater depth, distance to faults and cities had the highest weights whereas elevation and slope criteria had the lowest weights. The consistency ratio for the weighting process was 0.08, which was less than 0.1, presenting the consistency and credibility of the weighting process. According to the WLC method, major parts of north-west, west and north of the area under study were identified as optimal sites. According to the results of Electre model, a site with an area of 694 hectares located in the west of city was identified as the best alternative. Conclusion: The results showed that the Electre method along with multi-criteria evaluation methods can have high performance in locating sanitary municipal solid waste disposal.
Golnar Asadi Shirin; Mehdi Gholamalifard
Abstract
Background&Objectives: In regard to the serious consequences of improper waste disposal, environmental impact assessment techniques are used to evaluate the different scenarios for waste management and minimize the negative impacts. The aim of this study was the use of Iranian Matrix ...
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Background&Objectives: In regard to the serious consequences of improper waste disposal, environmental impact assessment techniques are used to evaluate the different scenarios for waste management and minimize the negative impacts. The aim of this study was the use of Iranian Matrix and RIAM to minimize environmental impacts in Qaemshahr landfill and presenting suitable methods for efficient waste management Matrial&Methods: In this study, the existing condition of Qaemshahr landfill was compared with human’s environmental criteria for MSW landfills based on Department of the Environment (DOE) of Iran. Meanwhile, EIA of Qaemshahr solid waste landfill was carried out with two methods, RIAM and Leopold Matrix. The upgrading of existing landfill, reconstruction with compost plant and relocation of landfill were evaluated according to physiochemical, physicochemical (PC), biological-ecological (BE), sociological/cultural (SC), economical/operational (EO) economical-social and cultural components. Results: The results showed that Qaemshahr landfill lacks the environmental criteria for MSW landfills. Also, the RIAM and Iranian matrix results indicated that upgrading of existing landfill, construction of compost plant, relocation and construction of the sanitary landfill have total environmental scores as -793 and -2.26, -387 and -2.22 , -69 and -0.76 respectively. Conclusion : It is noticeable that the current process of landfill in Qaemshahr will lead to harmful health consequences. So, construction of landfill space (the third option) was chosen as the most suitable option with as little harm as possible on the environment.