فهرست مطالب

Global Journal of Environmental Science and Management - Volume:6 Issue:1, 2020
  • Volume:6 Issue:1, 2020
  • تاریخ انتشار: 1398/10/11
  • تعداد عناوین: 10
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  • J.A. Araiza Aguilar *, M.N. Rojas Valencia, R.A. Aguilar Vera Pages 1-14

    The objective of this study was to develop a forecast model to determine the rate of generation of municipal solid waste in the municipalities of the Cuenca del Cañón del Sumidero, Chiapas, Mexico. Multiple linear regression was used with social and demographic explanatory variables. The compiled database consisted of 9 variables with 118 specific data per variable, which were analyzed using a multicollinearity test to select the most important ones. Initially, different regression models were generated, but only 2 of them were considered useful, because they used few predictors that were statistically significant. The most important variables to predict the rate of waste generation in the study area were the population of each municipality, the migration and the population density. Although other variables, such as daily per capita income and average schooling are very important, they do not seem to have an effect on the response variable in this study. The model with the highest parsimony resulted in an adjusted coefficient of 0.975, an average absolute percentage error of 7.70, an average absolute deviation of 0.16 and an average root square error of 0.19, showing a high influence on the phenomenon studied and a good predictive capacity.

    Keywords: Explanatory variables, forecast model, Multiple Linear Regression, statistical analysis, Waste generation
  • A.C. Affam * Pages 15-30
    Conventional steam activation pyrolysis of waste materials such as oil palm kernel shell for production of biochar was investigated using central composite design. Conventional steam activation was carried out via an initial carbonization of oil palm kernel shell to obtain biochar and thereafter steam activation of the biochar using the conventional heating to produce activated carbon. Additionally, removal of chemical oxygen demand and colour was studied alongside the production. Optimum yield was obtained at about 90 min and 725oC. Out of the time duration, 80 min was for carbonation and 10 min was for steam activation. Further extension of time was not significant whereas increasing temperature was able to increase the pores found on the biochar. Under the optimum condition, fixed carbon was 19.39%, chemical oxygen demand and colour removal were 32.02 and 61.15%, respectively at 90 min adsorption time. However, when time was extended to 120 min, chemical oxygen demand (48.2%) and colour (94.19%) removal were achieved. The Brunauer–Emmett–Teller surface area and micropore area of the oil palm kernel shell based activated carbon was 620.45 m2/g and 550.4 m2/g, respectively. The conventional steam activation is an effective method that can be employed in production of activated carbon from waste oil palm kernel shell.
    Keywords: Central composite design, Conventional heating, Oil palm kernel shell, Response surface methodology, Steam activation
  • H.T. Abdel Hamid *, W. Wenlong, L. Qiaomin Pages 31-46
    Flash flood has been increasing in the Khartoum area, Sudan due to geographical conditions and climatic change as heavy rainfall and high temperature, therefore the present work tried to estimate the sensitivity of flash flood. The present work proposes an advanced technique of flood sensitivity mapping using the method of analytical hierarchy process. Ten factors as elevation, slope, distance from the network, land use, density of the drainage, flow accumulation, surface roughness, stream power index, topographic wetness index and curvature of the topography were digitized and then contributed in the mapping of Flash flood. Remote sensing data were integrated with analytical hierarchy process to determine the flood sensitive area in Sudan. The model was applied and completed as the consistency ratio was mostly reasonable (< 0.1). Based on the proposed model, about 75.56 Km2 (12.26 %), 156.14 Km2 (25.33%), 169.89 Km2 (27.56 %), 141.40 Km2 (22.94 %) and 73.50 Km2 (11.92 %); were classified as no susceptible, low susceptible, high susceptible, moderate susceptible and very highly susceptible to flooding. The present study showed a high variation in flood sensitivity due to climatic change and geographic condition. This index can be modified and applied in areas of the same characteristics of climatic conditions as one of the main recommendation in the study area. The study showed that poor infrastructure and lack of preparedness were the main causes of the disaster of flood in Sudan. This study merely demonstrated the critical analysis of geospatial mapping in proper mitigating, sustainable development and great monitoring the negative effects of flooding along the Khartoum region to reduce hazards of flood.
    Keywords: Analytical Hierarchy Process (AHP), Disaster, Flash flood, Remote sensing (RS), Shuttle radar topography mission- Digital elevation model (SRTM-DEM)
  • P. Bhuyar, M.H. Rahim, S. Sundararaju, G.P. Maniam, N. Govindan * Pages 47-58
    Seaweeds can produce variety of bioactive components for the benefits of humans. Malaysia is one of the countries to produce red seaweeds, which are popular secondary metabolites. Kappaphycus species, largest tropical red algae exhibit the high growth rate. It was reported that its biomass can grow double in just 15 to 30 days. Therefore, this investigation emphasized on two extraction methods such as hot water and ethanolic Soxhlet extraction to extract the bioactive compounds from Kappaphycus alvarezii. Both of theseextractions were screened to produce antimicrobial and antioxidants compounds. Total phenolic content and ferric reducing assays were employed to quantify antioxidant properties. Whereas, the disc diffusion assays were used to study antibacterial activity. The results reported the highest phenolic content for ethanolic extract (20.25 ± 0.03 mg gallic acid equivalents per gram of extract). On the other hand, the value of phenolic content was slightly decreased 19.1 ± 0.81 mg gallic acid equivalents per gram of extract for the hot water extract. It was also found that both the extracts were potentially capable of balancing reactive oxygen species. Disc diffusion assay results indicated that the extract of red alga K. alvarezi were more efficient against B. cereus. Among the fatty acids determined levoglucosenone and 4-Pyridinemethanol were present in high percentages in hot water extract whereas Hexamethyl- cyclotrisiloxane followed by 1, 2, 5- Thiadiazole-3-carboxamide, 4-[(2-chloroethyl) amino]-N-(2-hydroxyethyl) were present in ethanolic extract of K. alvarezi. The present study concluded that, hot water extracts of K. alvarezii can be used for large scale production of bioactive compounds utilizing an easily available potential seaweed. Future research of red seaweed will be highly important for pharmaceutical and medicinal field as well as a homogenizer in milk products, toothpaste and jellies in other industrial applications.
    Keywords: Bioactive components, Gas chromatography–mass spectrometry, Kappaphycus alvarezii, Reactive Oxygen Species, Red seaweed, Soxhlet-extraction
  • S. Ahmed, I. Kayes *, S.A. Shahriar, M. Kabir, M.A. Salam, S. Mukul Pages 59-72
    Soil salinity is considered as one of the major challenges in coastal agriculture in Bangladesh yet geographical extent of soil salinity and nutrients status have received little or no attention. This study investigated the patterns of soil salinity, total nitrogen, phosphorous, potassium and sulfur between agricultural and fallow land along a 90 km distance from the coastline in Noakhali, Bangladesh. Soil samples were collected from three depths (0, 10, and 30cm) in four different locations from coastline towards inland (0, 30, 60, and 90km) following a systematic random sampling. Soil salinity and total nitrogen, phosphorous, potassium and sulfur were analyzed by fitting fixed effect linear models for a full factorial design and then inverse distance weighted interpolation technique was applied to map spatial patterns of selected soil parameters. Highest soil salinity and sulfur were recorded in surface soils at coastline (0 km), whereas least in 90 km far from coastline. Soil depth resulted significant differences in phosphorous, potassium and showed significant interactions among the distant points. This study delineates the soil nutrients patterns and salinity as baseline information to explain salinity driven soil nutrient dynamics in coastal region of Bangladesh.
    Keywords: Coastal soil, Coastal agriculture, land use, interpolation technique, Inverse Distance Weighted (IDW) Salinity, Soil nutrients
  • F. Mohammadi, M.A. Abdoli *, M. Amidpour, H Vahidi, S. Gitipour Pages 73-84

    Approximately 2.4 million tons of bagasse are produced each year in Iran, most of which are currently treated as waste adding to serious environmental concerns. Application of bagasse for energy production is a sustainable solution to supply the required energy within the sugar refineries and export the surplus electricity to the grid. Currently, the energy demand in Iranian sugar mills is mainly supplied by fossil fuels (natural gas or mazut). Bagasse fluidized bed and fixed bed gasification plants would respectively lead to save 59,250 and 21,750 tons of CO2 annually, compared to gas power plants of the same scale. The present study aims to compare the environmental economic analysis of electricity generation in 10-MW gas-fired power plants with that electricity generation in bagasse gasification plants (with fluidized bed and fixed bed reactors) exemplarily in Iran. The bagasse fluidized bed gasification option (with IRR of 28.6%) showed the most promising economic viability compared to bagasse fixed bed gasification and gas power plant cases with IRR values of 25.09 and 21.94%, respectively. Furthermore, bagasse gasification options were potentially characterized by a better environmental performance compared to fossil-fuelled options. On the other hand, the obtained levelised cost of electricity at gas power plants (2 cents/kWh) was lower than the global range and lower than bagasse gasification cases (7-9 cents/kWh). The results revealed the vital need of biomass power plants to governmental support in order to compete with fossil power plants by participation of private sector.

    Keywords: Combined heat, power (CHP), Economic evaluation, Gasification, Levelised cost of electricity (LCOE), Natural gas power plant, Sugar cane bagasse
  • M. Camara, N.R.B. Jamil *, F.B. Abdullah Pages 85-96
    Rapid development and population growth have resulted in an ever-increasing level of water pollution in Malaysia. Therefore, this study was conducted to assess water quality of Selangor River in Malaysia. The data collected under the river water quality monitoring program by the Department of environment from 2005 to 2015 were used for statistical analyses. The local water quality indices were computed and a trend detection technique and cluster analysis were applied, respectively, to detect changes and spatial disparity in water quality trends. The results showed that the river water is of good quality at all stations, with the exception of 1SR01 and 1SR09 located upstream, which recorded moderate water quality indices of 68 and 71, respectively. The results of trend analysis showed downward trends in dissolved oxygen, biochemical oxygen demand and ammonia nitrogen, for most water quality stations, as well as increasing trends in chemical oxygen, suspended solids, pH and temperature for most stations. In addition, the results of cluster and time series analyses showed that the trend variation in dissolved oxygen, pH, and temperature between the station clusters is relatively low as compared to chemical oxygen demand, biochemical oxygen demand, suspended solids, and ammonia nitrogen. With the peak concentration of 13 mg/L for dissolved oxygen observed in cluster 2 in 2014, and the highest decrease in suspended solids (8 mg/L) observed in cluster 1 for 2015. This finding demonstrates that these combined statistical analyses can be a useful approach for assessing water quality for adequate management of water resources.
    Keywords: monitoring network, Selangor River, statistical analysis, trend detection, Water quality
  • A.B. Imran, K. Khan *, N. Ali, N. Ahmad, A. Ali, K. Shah Pages 97-108
    Forest’s ecosystem is one of the most important carbon sink of the terrestrial ecosystem. Remote sensing technology provides robust techniques to estimate biomass and solve challenges in forest resource assessment. The present study explored the potential of Sentinel-2 bands to estimate biomass and comparatively analyzed of red-edge band based and broadband derived vegetation indices. Broadband indices include normalized difference vegetation index, modified simple ratio and atmospherically resistant VI. Whereas, red-edge band indices include two red-edge normalized difference vegetation index and sentinel-2 red-edge position. Results showed that red-edge band derived spectral indices have performed better than the Broadband indices. The coefficient of correlation for normalized difference vegetation index, modified simple ratio and atmospherically resistant-VI was 0.51, 0.44 and 0.31 respectively, On the other hand, red-edge band indices showed higher correlation of R2 0.62, 0.64 and 0.55, respectively. Similarly, in stepwise regression red-edge normalized difference vegetation index (using band 6) was selected in final model (as overall R2 of the model was 0.60) while all other indices were removed because they have non-significant relationship with the biomass. Accuracy assessment shown the red-edge index has highest R2 (0.64) and least error of (31.29 t/ha) and therefore the study concluded that narrowband indices performed better to estimate biomass and thus final model contained only red-edge index to predict biomass over the study area. The study suggests that more in-depth research should be conducted to explore further properties of red-edge indices for vegetation parameters prediction.
    Keywords: Red-edge (RE), Red-edge normalized difference vegetation index (RENDVI), Sentien-2, Sentinel-2 red-edge position (S2REP)
  • M. Samimi *, M. Shahriari Moghadam Pages 109-118
    phenol and phenolic compounds are among the most recognized environmental pollutants which exist in industrial wastewater and enter the biological cycles due to the solubility in water. Bioremediation is one of the cost-effective and Eco-friendly methods for phenol removal. In this study, the most effective phenol-degrading bacterial strain was isolated and identified from the shores of the Oman Sea by 16S rDNA. The optimal conditions of various factors, such as pH, temperature, carbon to nitrogen ratio and salinity for the phenol biodegradation, were determined using the experimental design based on Taguchi method with L9 array (34). Ability of the isolated strain (Halomonas elongata strain O-CH1) in degradation of different phenol concentrations was analyzed. The optimum operating conditions for phenol removal were determined in pH value of 8, temperature of 35 ˚C, carbon to nitrogen ratio of 100:30 (g/L) and salinity of 35 (g/L). In these conditions, 97% of the phenol was removed from the mediums. According to the optimization results, salinity and pH were the most influential factors in the biodegradation of phenol. The O-CH1 was able to grow and degrade phenol at concentrations of 250 mg/L to 1500 mg/L. Considering the high potential of this strain for phenol degradation, determining the optimal conditions for the biodegradation and its efficacy at high concentrations of phenol, the findings in this study can be used in the biological treatment of phenolic wastewater.
    Keywords: Bioremediation, Phenol, Optimization, Biodegradation, Taguchi
  • M. Tadjuddah *, Abdullah, S. Kamri, N.I. Wianti Pages 119-132

    Wakatobi National Park has a tropical marine ecosystem with typically dynamic aquatic resources, and it also has a potentially massive number of groupers such as red (Plectropomus leopardus) and black groupers (Plectropomus areolatus). However, the sustainability of the grouper resources has not been managed effectively and environmentally friendly. This study aims to determine the susceptibility level of red and black groupers in the research area based on the productivity and susceptibility analysis. This study was conducted from May to November 2018, in which the data were collected from the grouper’s fishermen using hand line with simple random methods as a fishing gear in Wanci and Tomia islands of Wakatobi. Based on the collected data, productivity attribute of red groupers is at 1.8, and the susceptibility level is at 2.08, while the black groupers have 1.7 for the productivity attributes and 2.0 for their susceptibility level. Based on the susceptibility index of both types of fish, it indicates that red groupers are at 1.61, and the black groupers’ susceptibility level is at 1.64. This study implies that the susceptibility index of red and black groupers at Wakatobi National Park is moderate which means that the groupers as a matter of fact experience fishing pressure. Therefore, some sustainable efforts to effectively and environmentally friendly manage the fishing activity in the island need to be done in the future.

    Keywords: Grouper, Plectropomus sp, Productivity, susceptibility analysis (PSA), Susceptibility level, Wakatobi National Park