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Treatment of dairy wastewater by graphene oxide nanoadsorbent and sludge separation, using In Situ Sludge Magnetic Impregnation (ISSMI) Полный текст
2018
Falahati, Faezeh | Baghdadi, Majid | Aminzadeh, Behnoush
The present research investigates the ability of graphene oxide nanosheets for treatment of dairy wastewater, using In Situ Sludge Magnetic Impregnation” (ISSMI) to separate sludge after adsorption process. To increase the interaction between magnetic nanoparticles and graphene oxide, the former has been functionalized, using 3-Aminopropyl triethoxysilane, with the synthesized graphene oxide and magnetic nanoparticles being characterized by FT-IR, SEM, and NCHS analysis. The experiments have been conducted on the effluent of Pegah factory. The batch adsorption experiments have been carried out to investigate the effect of adsorbent dose, contact time, and pH on the removal of total nitrogen, total phosphorus, COD, and turbidity. At adsorbent dose of 320 mg L-1, the removal efficiencies of 90, 80, 84, and 94% have been observed for TN, TP, COD, and turbidity, respectively. The adsorbent data has been modeled by Langmuir and Freundlich isotherms, giving results that are compatible with Freundlich isotherm. TN, TP, and COD are mostly particulate materials in dairy wastewaters; therefore, when nanosheets aggregate, particulate materials are trapped between GO nanosheets; as a result, pollutants are distributed heterogeneously on the adsorbent's surface. Consequently, adsorption does not occur as monolayer on the surface of GO; for this reason, adsorption follows Freundlich model. Maximum absorption capacity of the adsorbent turns out to be 730 mg g-1 for total nitrogen, 600 mg g-1 for total phosphorus, 26000 mg g-1 for COD, and 5500 mg g-1 for turbidity. Adsorption kinetic has been studied with the first and second order equation, giving results that are compatible with second order equation.
Показать больше [+] Меньше [-]Spatio-temporal variability of aerosol characteristics in Iran using remotely sensed datasets Полный текст
2018
Rezaei, Mohammad | Farajzadeh, Manuchehr | Ghavidel, Yousef | Alam, Khan
The present study is the first attempt to examine temporal and spatial characteristics of aerosol properties and classify their modes over Iran. The data used in this study include the records of Aerosol Optical Depth (AOD) and Angstrom Exponent (AE) from MODerate Resolution Imaging Spectroradiometer (MODIS) and Aerosol Index (AI) from the Ozone Monitoring Instrument (OMI), obtained from 2005 to 2015. The high concentration of AOD and AI values (representing high-high cluster) have been observed in the southwest and east regions, while their low concentrations (representing low-low cluster) have been found in the high mountainous areas. Based on AE values, Iran has been divided into three distinct regions, including fine, mixture, and coarse aerosol modes in each season. Results show that the maximum/minimum area under fine aerosols mode has occurred in the autumn, covering an area of 84.15% and in the spring, covering an area of 40.5%. In the case of coarse mode, the maximum/minimum area has been found in the spring, covered area=53.5% / in the Autumn covered area=12. 5%. The different aerosol modes regions strongly coincide with the topographical structure. To analyze the relation between aerosol properties and topography, Aerosol Properties Index (API) has been developed by combining OMI and MODIS datasets. API is a simple indicator, capable of showing the degree of aerosol coarseness in each pixel. There is a negative correlation between API and topography over the studied region, meaning that aerosol concentrations are high in the lowlands, but low in the highlands. However, this relation differs in various geographic regions, as Geographically Weighted Regression (GWR) model shows a higher determination coefficient in all seasons, in comparison to Ordinary Least Squares (OLS).
Показать больше [+] Меньше [-]Soundscapes of Urban Parks in and around Bhubaneswar and Puri, Odisha, India: A Comparative Study Полный текст
2018
Swain, Bijay | Goswami, Shreerup
Anthropogenic noise is debatably one of the most common threats to national parks' resources. Park visitors and workers generally suffer from adverse effects of noise from on- and off-road vehicles. The parks, studied here, are located in strictly urban areas, surrounded by streets with intense vehicle traffic. This study assesses the soundscape of urban parks in two cities of Odisha State, on the basis of acoustic field measurements and interviews. Noise descriptors in and around three different parks in Bhubaneswar and Puri cities have been measured and analyzed. A field experiment has been conducted with 330 participants in three parks, representing urban natural environment. The questionnaire comprised identification of the interviewee, characteristics of the user's profile in terms of his/her use of the park, and aspects of individual’s perception of the soundscape and environmental quality of the park. Positive correlation has been established among the noise levels of these three parks. The present study reveals that the acoustic sound levels of all the investigated parks are more than 50 dB (A) [permissible limit, established by Central Pollution Control Board (CPCB) for green parks]. Considering the urban elements and acoustical characteristics, it can be concluded that all the parks are affected by several factors such as urban planning, land use, main traffic routes, type of public transportation, and its internal sounds.
Показать больше [+] Меньше [-]Assessment of Solid Waste Management Practices in Bahir Dar City, Ethiopia Полный текст
2018
Birara, E. | Kassahun, T.
Even though solid waste management has become a major public health and environmental concern in urban areas of Ethiopia, only 2% of the population receive solid waste management services. The primary objective of this study is to assess solid waste management practices of Bahir Dar City. The technique of multistage random sampling has been employed to draw 350 households for this study, with both quantitative and qualitative primary data put into good use. Finally, the quantitative data has been analyzed by means of descriptive statistics with the results indicating that 78% of the respondents feel that the current solid waste management service is far below the required level; whereas, 22% of the respondents show satisfaction with the existing waste management service. The municipality has planned to provide solid waste management service for the residents once a week, but the survey results demonstrate that only 29% of the sample households received solid waste management services weekly, indicating that the performance of solid waste management service is low. Among 350 households, a sum of 66.6% practice illegal solid waste disposal with the remaining 33.4% waiting until solid waste collectors come to the area to take the waste away. Therefore, participation of urban households, micro and small enterprises, and governmental and non-governmental organizations plays a great role to upgrade the existing low status of solid waste management services.
Показать больше [+] Меньше [-]Emergence and Dispersion of Resistance Genes by the Aquatic Environment: a review Полный текст
2018
Barcelos, D. H. F. | Knidel, Carina | Fernandes, C. G. L.
The association of the emergence of bacterial resistance to clinical environments is common; however, aquatic environments, especially the polluted ones, also play a key role in this regard. Aquatic environments can act as facilitator for the exchange of mobile elements, responsible for resisting antibiotics. They even may stimulate the emergence and selection of these elements through contaminants or the natural competition between bacterial phyla. Currently there is a large number of highly-reliable resistance genes, which is selected in aquatic environments, mostly due to several types of pollution, such as the mcr-1 gene that causes resistance to one of the antibiotics, available in the market, namely colistin. Thus, the present review aims to show a range of impacts capable of selecting bacterial resistance in the environment, thus clarifying this environment's role in dispersion of resistance.
Показать больше [+] Меньше [-]Environmental Situation of an Agricultural Area in Akure, Nigeria, Based on Physico-Chemical Properties of Rainwater Полный текст
2018
Abulude, Francis | Ndamitso, M.M. | Abdulkadir, A
Acid rain still poses a global problem today, exerting many adverse effects on man, animal, and materials. As its research question, the present study tries to find out whether or not acid rains exist in Akure, Nigeria. For so doing, it determines physico-chemical properties of rain water samples, namely pH, temp, Electrical Conductivity (EC), TDS, acidity, SO4-, NO2-, Cl-, and Free CO2. According to the results, the pH ranged between 6.0 and 7.8, never falling below 5.6 which is an indication of acid rain. Also, the minimum EC was 3µS/cm and the maximum, 201µS/cm. Moreover, TDS was between 1 and 100mg/L, while Free CO2 had a mean of 23.00 and Standard Deviation of 6.16. The dominant ion was SO4- (10-11%), followed by NO3-, and Cl-. Results from the first six months (July-December 2015) reveal slight correlations in the following: TDS with pH (0.532), EC and pH (0.501), Temp and Free CO2 (0.59), whereas strong correlations have been recorded in the following parameters: Acidity with pH (0.71) and Temperature (0.69), NO2- with pH (0.96) and acidity (0.96), SO4- with temp (0.68) and NO2- (0.83), and finally Cl- with Free CO2 (0.61), NO2- (0.73), and Cl- (0.65). It can be concluded that in the environment under this study there have been no acid rain within the period.
Показать больше [+] Меньше [-]Experimental and Theoretical Study on the Ability of Microbial Fuel Cell for Electricity Generation Полный текст
2018
Ali, Ahmed | Al-Mussawy, H.A. | Hussein, M.J. | Hamadi, N.J.
The present study aims at designing a promising Microbial Fuel Cell (MFC) to utilize wastewater in order to generate electricity. Two types of salt bridge have been used in MFC (KCl and NaCl). The maximum electricity generation with 1M KCl and NaCl has been 823 and 713 mV, respectively. Varied salt concentrations (0.5M, 1M, 2M, and 3M) of salt bridge in MFC have been analyzed with different factors like temperature, type of electrode, configuration, and surface area of electrode being studied. The optimum temperature is found to be 32Co, with the optimum type of electrode being graphite rod, while the optimum configuration and surface area of electrode is graphite plate with surface area of 183.6 cm2. Artificial Neural Network (ANN) has been employed to predict voltage production of MFC and compare it with the experimental voltage. Multiple correlation methodology has optimized the voltage production with the correlation coefficient (R2) being 0.999.
Показать больше [+] Меньше [-]Potential Assessment of Geomorphological Landforms of the Mountainous Highland Region, Haraz Watershed, Mazandaran, Iran, Using the Pralong Method Полный текст
2018
Amiri, Mohammadjavad | Nohegar, Ahmad | Bouzari, Shahrzad
As the largest service industry in the world, tourism plays a special role in sustainable development. Geomorphic tourism is known to be a segment of this industry with lower environmental impact and underlying causes that explain lower demand; therefore, it is essential to study, identify, assess, plan, and manage natural tourist attractions. As such, the present study assesses the ability of geomorphological landforms of Haraz watershed, one of the major tourism areas of Iran. In this regard, the features of geomorphologic landforms, including Mount Damavand, the Damavand Icefall, Shahandasht Waterfall, Larijan Spa, and Deryouk Rock Waterfall in different parts of the Haraz watershed have been compared from the standpoint of geotourism features. To assess these landforms, geological maps, topographic and aerial photos, satellite imagery, Geographic Information Systems (GIS), and data field have been used as research tools. Evaluation results demonstrate that the average of scientific values in these landforms’ catchment (with 0.76 points) has been greater than the average of other values. These high ratings show the landforms’ potentials to be informative to those examining them for the purpose of education as well as tourist attraction. Through proper planning and understanding of its both merits and demerits, this type of tourism can play an important role in national development and diversify regional economies.
Показать больше [+] Меньше [-]A Comparative Study of Air Pollution Tolerance Index (APTI) of Some Fruit Plant Species Growing in the Industrial Area of Sfax, Tunisia Полный текст
2018
zouari, mohamed | Elloumi, Nada | Mezghani, Imed | Labrousse, pascal | Ben Rouina, bechir | Ben Abdallah, Ferjani | Ben Ahmed, chedlia
Air Pollution Tolerance Index (APTI) is an important tool to screen out plants, based on their tolerance or sensitivity level to different air pollutants. The present study has been conducted to evaluate APTI of four different plant species around polluted and unpolluted industrial site in Sfax, Tunisia. In order to determine the susceptibility level of the selected plant species, it has used four physiological and biochemical parameters like leaf relative water content, ascorbic acid content, chlorophyll content, and leaf pH to compute the APTI values. The results of the study reveal that among the four studied plant species, Olea europaea (APTI = 20.09) and Phoenix dactylifera (APTI = 17.10) are the most tolerant species, whereas Ficus carica (APTI = 8.87) and Morus alba (APTI = 7.49) are the most sensitive ones. The present study suggests that the most tolerant species, i.e., olive and date palm, can be planted in polluted sites for both air pollution abatement and aesthetic improvement. While, the sensitive species, namely common figand white Mulberry, help indicating air pollution and should be utilized as bio-indicators.
Показать больше [+] Меньше [-]Bayesian Econometrics Approach in Determining of Effecting Factors on Pollution in Developing Countries (based on Environmental Performance Index) Полный текст
2018
Fakher, Hossein-Ali | Ahmadian, Majid | Abedi, Zahra | Shaygani, Bita
Emphasis on sustainable development and the need to protect the environment as well as the adverse effects of environmental pollution on the quality of life have made environmental protection one of the main concerns of economic policymakers. For this purpose, approaches to improve the quality of the environment and the factors affecting it have triggered extensive theoretical and empirical studies over the past few decades. These issues have caught the attention of economic analysts. Accordingly, the main objective of this study is to investigate pollution determinants in developing countries from 1996 to 2016, using Bayesian Model Averaging Method. Given the fact that the weighted mean square coefficient of GDP is positive, the Environmental Kuznets Curve (EKC) Hypothesis can be confirmed with a high degree of certainty. The probability of this variable's effect is 0.98%, being partially a component of each of the 10 optimal models which highlights the great importance of this variable to explain the environmental performance. Energy consumption variables for each unit of GDP and value added of industry sector are placed in the second and third ranks with effectiveness probability of 0.89 and 0.85, respectively. They also have a negative impact on environmental performance. Thus, energy consumption per unit of GDP is considered one of the elements of 8 out of 10 optimal models, while the value added of the industrial sector is an element of 7 out of 10 models. This highlights the relative importance of these variables in explaining environmental performance.
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