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Global Journal of Environmental Science and Management - Volume:4 Issue: 2, Spring 2018

Global Journal of Environmental Science and Management
Volume:4 Issue: 2, Spring 2018

  • تاریخ انتشار: 1397/01/05
  • تعداد عناوین: 10
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  • B. Seng, T. Fujiwara, B. Seng Pages 113-126
    Solid waste management is challenging in Phnom Penh city, Capital of Cambodia. The only one formal treatment taken is the final disposal of mixed waste into an open dumpsite. The current study analyses the physical and chemical characteristics of municipal solid waste disposed of in the dumpsite to assess their suitable handling methods. The current study found that the major compositions of waste are food waste (49.18%) and plastic (21.13%), and recyclable waste shares about 17.28% of the total. On average, it contains 60.92% moisture, 35.89% combustible, 3.19% ash, 58.32% carbon and 1.05% nitrogen. High calorific value is 10.03 MJ/kg when the low calorific value is 7.77 MJ/kg. The moisture content is too high to meet the technology demands, especially in the rainy season. It seems workable for incineration without energy recovery. Gasification for melting and incineration with energy recovery are only suitable for the dry season. If the solid waste is well pre-separated, material recovery could be one of the suitable handling methods. Food waste, wood and leave could be digested in the one-stage continuous wet system and co-composted, and plastic is appropriate for refuse-derived fuel generation. The current study recommends that the waste pre-separation should be requisite for any handling methods.
    Keywords: Open dumpsite, Pre-separation, Recovery, Solid waste management, Suitable handling method
  • Kinematic runoff and erosion model efficiency assessment for hydrological simulation of semi-arid watersheds
    S.M. Tajbakhsh, H. Memarian, M. Sobhani, A.H. Aghakhani Afshar Pages 127-140
    Hydrologic modeling of semi-arid watersheds is imperative for the development of appropriate water and soil conservation plans. In the current study, the efficiency of Kinematic Runoff and Erosion model-version 2 (K2) model was used to evaluate water discharge and sediment load simulation of Bar watershed, located in the north-eastern part of Iran. The K2 model relies on the kinematic wave approach to route surface flow. The drainage network and planes are discretized to represent the watershed. In order to evaluate the model, 3 and 2 reported rainfall incidents in various dates were selected for K2 calibration and validation, respectively. The multiplier approach was employed for model calibration. The results of sensitivity investigation revealed that the soil parameters Ks-CH, n and G had the highest impact on flow discharge. Through the calibration process, the Nash-Sutcliff Efficiency and the coefficient of determination as fitting metrics for water discharge simulation (based on event #2, dated 16 March 1992) were estimated to be 0.78 and 0.88, respectively. According to the aggregated measure, the highest K2 efficiency was obtained during the calibration process based on event #2. Other storm events were resulted in a good simulation, as well. During the validation process, K2 simulation (based on event #4, dated 07 March 1991) led to the Nash-Sutcliffe Efficiency and R2 of 0.77 and 0.71, respectively. The K2 calibration for sediment load simulation was performed through the alterations of the Pave and Rainsplash parameters. The bias percentages between simulated and observed total sediment loads based on events #2 and #4 were 5% and 16%, respectively. Conclusively, the K2 model showed an acceptable robustness in the hydrological simulation of Bar watershed as a representative semi-arid watershed in northeast of Iran.
  • B. Te, B. Wichitsathian, C. Yossapol, W. Wonglertarak Pages 141-152
    Mesoporous pellet adsorbent developed from mixing at an appropriate ratio of natural clay, iron oxide, iron powder, and rice bran was used to investigate the optimization process of batch adsorption parameters for treating aqueous solution coexisting with arsenate and arsenite. Central composite design under response surface methodology was applied for optimizing and observing both individual and interactive effects of four main influential adsorption factors such as contact time (24-72 h), initial solution pH (3-11), adsorbent dosage (0-20 g/L) and initial adsorbate concentration (0.25-4.25 mg/L). Analysis of variance suggested that experimental data were better fitted by the quadratic model with the values of regression coefficient and adjusted regression coefficient higher than 95%. The model accuracy was supported by the correlation plot of actual and predicted adsorption efficiency data and the residual plots. The Pareto analysis suggested that initial solution pH, initial adsorbate concentration, and adsorbent dosage had greater cumulative effects on the removal system by contributing the percentage effect of 47.69%, 37.07% and 14.26%, respectively. The optimum values of contact time, initial solution pH, adsorbent dosage and initial adsorbate concentration were 52 h, 7, 10 g/L and 0.5 mg/L, respectively. The adsorption efficiency of coexisting arsenate and arsenite solution onto the new developed adsorbent was over 99% under the optimized experimental condition.
    Keywords: Analysis of variance, Arsenic removal, Central composite design, Mesoporous adsorbent, Response surface methodology
  • Assessment of temporal and spatial eutrophication index in a water dam reservoir
    F. Esfandi, A.H. Mahvi, M. Mosaferi, F. Armanfar, M. Hejazi, S. Maleki Pages 153-166
    Eutrophication is considered as a serious problem in water reservoirs. Awareness about the eutrophic status of each reservoir could help in providing a better understanding of the problem in a global scale. The present study was conducted to assess temporal and spatial eutrophication index in a water reservoir (Sahand dam) in the northwest of Iran. Physico-chemical parametres that are effective on eutrphic condition occurrence were analyzed, and trophic state index was calculated on a scale of 0-100 by measuring Secchi disk depth, chlorophyll a, total phosphorus, total nitrogen, total suspended solids, and phosphorus P/N ratio. Moreover, using the overlapping, the reservoir was mapped based on the mentioned index. Seasonal variation of dissolved solids in the reservoir was recorded due to precipitation and subsequent dilution and evaporation. Thermal stratification was observed during the summer months. The total trophic state index value was calculated as 55.5- 58.07, with minimum value belonging to P/N and maximum value belonging to suspended solids for individual parameters. There were some spatial and temporal differences for trophic state index in the reservoir. It was found that the whole area of the reservoir was in almost moderately upper-mesotrophic condition and in some target stations it was very close to eutrophic condition. The worst condition was observed in Qaranqu River as the main input to the reservoir. Due to the significant impact of suspended particles resulting from erosion of the surrounding lands on TSI value, there is an urgent need for mitigation measures to intercept eutrophication.
  • Urban solid waste characterization in the east part of Black Sea region
    K.O. Demirarslan, B.Y., Ccedil, Elik Pages 167-182
    In the current study, the solid waste characterisation that belongs to Artvin city centre, which is located in East Black Sea Region of Turkey, were searched. The study has the feature of being the first study for the country of Artvin in terms of study. The field of study is composed of 7 neighborhoods and those can be separated into 3 groups as low, middle and high level of income. In this study, 11 kind of waste were examined, which are organic, paper, plastic, glass, metal, ash, electronic, textile, garden waste, hazardous and others. The effect of seasons on the amount of waste was examined; also, the relationship between the amount of waste and the level of income was also examined by using the two-way ANOVA analysis. Furthermore, all ratios of wastes that are located in Artvin city centre were searched. According to that, the waste ratios, occurs in one year, of all neighborhoods in the Artvin city centre are found as 61.06% organic, 10.28% paper, 9% plastic, 3.20% glass, 2.29% metal, 3.87% ash, 0.037% electronic, 1.58% textile, 1.35% garden waste, 0.51 % hazardous and 7.23% others. Those obtained values were compared with other similar studies in the literature. Moreover, for collecting recyclable wastes for the city centre 3 different methods are proposed named as methods collection from households, collection from buildings and collection from neighborhoods. These methods have been studied economically and the collection from buildings method is the most appropriate among these three methods.
  • Application of DEA technique in SWOT analysis of oily sludge management using fuzzy data
    H. Borgheipour, Z. Moghaddas, M. Abbassi, N. Abbaszadeh Tehrani Pages 183-194
    The proper management of oily sludge from petroleum products storage tanks is necessary because inappropriate methods for dredging of tanks may result in high costs and increased environmental pollution. The purpose of the current study is to rank the strategies outlined by strengths, weaknesses, opportunities and threats analysis using data envelopment analysis model, which provides enriched insights into management of waste from dredging of tanks. As a result, with the use of strengths, weaknesses, opportunities and threat analysis, the strengths, weaknesses, opportunities, and threats were determined and some management strategies for oily sludge were obtained. Afterward, fuzzy data envelopment analysis was used to prioritize the strategies. Using expert's opinions, strategies can be ranked and prioritized by solving the data envelopment analysis model according to the acquired optimal solutions. An important point in this method is that expert's opinions are also incorporated into the analysis. Sixteen strategies are presented based on the strengths, weaknesses, opportunities and threat analysis and prioritized based on fuzzy data envelopment analysis. Strategies number 14 and 10, based on weakness-opportunities and strengths-threats respectively are of first priorities. Therefore, the strategies such as development of executive instructions and guidelines, elaboration of duties of managers regarding waste management and construction of a suitable and centralized site for storing oily sludge according to environmental requirements could be strategically useful for the management of oily sludge from storage tanks.
  • R. Teimouri, T. Yigitcanlar Pages 195-206
    In the best practices, planning of urban green spaces is managed in such a way that it follows the key principles such as meeting per capita standards and providing accessible and balanced distribution of these spaces all across the city. In the context of emerging economy, these principles are unfortunately not followed strictly all times. In this study, it is attempted to investigate Tabriz city of Iran is in terms of ecological planning to quantitatively analyse its green space characteristics. The used methodology includes determining the relevant urban green space development indicators (e.g. accessibility, per capita supply, balanced distribution, and continuous development of urban green spaces) from the literature and using the secondary data collected from variety of sources to analyse the study area. The study seeks to provide a comprehensive view on status of green spaces in Tabriz in the light of ecological principles and indicators and GIS-based spatial analysis. Results indicate that: a) Green space per capita provision in Tabriz is much lower than the national and international standards (some districts offer only 0-1 sq.m. per capita green space); b) Districts of Tabriz do not have a balanced distribution of green spaces and access to green spaces on foot (only 18% of the population can access green spaces within a 5 minute walk); c) Except for the provided street side green spaces, all other passive or active types of green spaces in Tabriz are not continuously linked (no continuity to form a green corridor or linear greenways). This study also comes up with some recommendations for Tabriz and other cities with similar characteristics.
    Keywords: Ecological planning, Green space accessibility, Sustainable city, Sustainable urban development, Urban green spaces
  • M. Heshmati, M. Gheitury, M. Hosseini Pages 207-216
    In this study, to investigate the effects of runoff harvesting on soil properties in the semiarid forest, runoff harvesting through semi-circular bund was considered as a method to conserve soil and thereby combat tree mortality. In order to evaluate this hypothesis, runoff was harvested through the semi-circular bund affecting soil quality and moisture storage. The selected forest site is located in Kalehzard, Kermanshah, in Zagros region of western Iran. The experiment was a randomized complete block design with four treatment plots: bund with protection, protection treatment, bund without protection and control treatment. The results showed that the mean values of soil organic carbon in the bund with protection, protection treatment, bund without protection and control treatment were 2.35, 2.40, 1.90, and 1.80%, respectively, indicating no significant difference among them in the first year, while there were significant (p> 0.05) increases in the bund with protection and protection treatment after three years. Furthermore, coarse and very coarse soil aggregates increased significantly in the bund with protection treatment. This treatment also attributed to significant reduction in soil bulk density from 1.46 (in the first year) to 1.32 (in the third year), which enhanced soil moisture content. Finally it was found that bunds with protection significantly curtail dieback and adverse re-growing of stands due to the coupled effects of bund building and protection to curtail forest mortality in the semi-arid regions.
    Keywords: Bund construction, Bulk density, Kalehzard site, Protection treatment, Soil aggregate, Soil moisture
  • M.H. Rahimi, N. Kalantari, M. Sharifidoost, M. Kazemi Pages 217-230
    In this study, the quality of a treated wastewater for agricultural and irrigation purposes was investigated. 39 quality parameters were investigated at the entrance of an effluent channel to the destination plain in monthly time intervals during a year. The aim of this study was drawing an analogy between analyses results and the latest standards in the world (nationwide and internationally), the agricultural and irrigation usage indexes and the Wilcox diagram. The results showed that some parameters such as turbidity, total suspended solids, electrical conductivity, sodium, detergents, total coliform and focal coliform, ammonium, residual sodium carbonate, the Kelly’s Ratio and the Wilcox diagram were exceeding the permissible limit and are not suitable for agriculture and irrigation. It was found that the aquifers in the study area were polluted by natural salinity and geogenic source. As a result, application of the treated wastewater from Qom for agriculture and irrigation purposes needs to be revised and monitored. An action plan is also needed to manage a huge source of water and to avoid further environmental and health risks.
    Keywords: Effluent quality, Irrigation, Reuse, Salinity index, Water resource management
  • K. Afed Ullah, J. Jiang, P. Wang Pages 231-250
    Surface waters are the most important economic resource for humans which provide water for agricultural, industrial and anthropogenic activities. Surface water quality plays vital role in protecting aquatic ecosystems. Unplanned urbanization, intense agricultural activities and deforestation are positively associated with carbon, nitrogen and phosphorous related water quality parameters. Multiple buffers give robust land use land cover and water quality model and highlight the impacts of land use land cover characteristics on water quality parameters at various scales which will guide watershed managers for particular application of best management practices to enhance stream health. Traditionally, water quality data collections are based on discrete sampling and were analyzed through statistical techniques which were designed for spatially isolated measurements. Traditional multivariate statistical approaches uncover hidden information in water quality data but they are unable to expose spatial relationship. The complexity of information in water quality data needs new statistical approaches which uncover spatiotemporal variability. This review briefly discusses influences of land use land cover characteristics on surface water quality, effects of spatial scale on land use land cover- water quality relationship, and water quality modeling using various statistical approaches. Every statistical method has unique purpose, application and solves different problems. This review article pinpoints that how statistical approaches in combination with spatial scale can be applied to develop statistically significant land use land cover- water quality relationship for better water quality evaluation.
    Keywords: Agricultural activities, Land use land cover (LULC), Statistical approach, Urbanization, Water quality