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Global Journal of Environmental Science and Management - Volume:5 Issue: 1, Winter 2019

Global Journal of Environmental Science and Management
Volume:5 Issue: 1, Winter 2019

  • تاریخ انتشار: 1397/10/15
  • تعداد عناوین: 10
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  • M.B.T. Alivio*, G.R. Puno, B.A.M. Talisay Pages 1-16
    Increasing frequency and severity of flooding demands identification of flood hazard zones in Kalilangan, Bukidnon in response to the echoing need of better disaster preparedness via enhancing the understanding and awareness of the public on flood characteristics by integrating the use of two-dimensional hydrodynamic modeling and remote sensing. Flood simulation was carried out in a two-dimensional hydrodynamic model using hydrologic engineering center-river analysis system to derive the flood inundation area and flood depth of Kalilangan, Bukidnon. Thus, it was preceded by pre-processing of the model using software packages of hydrologic engineering center-hydrologic modeling system and ArcGIS along with interferometric synthetic aperture radar–digital elevation model, Manning’s roughness coefficient and precipitation data. Five different rain return flooding scenarios were simulated using rainfall intensity duration frequency data. Three zones of flood hazard were then set as low, medium and high. The result shows that most areas of Kalilangan are within the zones of medium to high hazard with residential buildings as the most flooded type of built-up structures. Flood hazard zone areas could be mapped at an accuracy of 79.51%. Thus, harnessing this potential approach offers cost-effective way of flood preparedness viewing hazard-prone areas with special attention and utmost importance.
    Keywords: Digital elevation model (DEM), Hydrologic modeling system (HMS), Interferometric synthetic aperture radar (IFSAR), Return period, River analysis system (RAS)
  • M.B. Kulkarni *, P.M. Ghanegaonkar Pages 17-30
    There is a great need to implement low-cost and user-friendly methods for further propagation of biogas technology in India. Environment unfriendly disposal of floral waste causes serious environmental pollution. Literature shows a limited research work regarding the anaerobic digestion of floral waste for biogas generation. The present experimental work aims to propagate floral waste as a sustainable source of biogas energy in India. Using different techniques like novel alkaline pretreatment, solar heating of the digester and co-digestion with food waste give enhanced biogas production from floral waste. A novel alkaline pretreatment of the floral waste using sodium carbonate and sodium bicarbonate gives an improvement in biogas output by 106%, with a saving in the cost of chemical pretreatment up to 96%, compared to traditional sodium hydroxide pretreatment. Also, solar heating of the digester increases the biogas output by 122% as compared to digesters in ambient conditions. Co-digestion of the floral waste with food waste also improves biogas output by 32.6%. Raw biogas from floral waste contains over 57% methane, which is higher than the previous studies. Large-scale application of the techniques can benefit the society.
    Keywords: Anaerobic digestion, Biogas, Co-digestion, Waste disposal, Chemical pretreatment, Solar heating of the digester
  • M.T.N. Cabasan *, J.A.G. Tabora, N. Cabatac, C.M. Jumao, as, J.O. Soberano, J.V. Turba, N.H.A. Dagamac, E. Barlaan Pages 31-42
    Understanding farmers’ perception is important in the development of sustainable and cost-effective integrated pest management strategies. Hence, farmers’ perception on rice insect pests and pesticide use was evaluated by selected 112 farmers composed of 77% males and 23% females, over the rice growing areas of North Cotabato, Central Mindanao, Philippines. 62% of farmers that were interviewed use pesticides based on the presence of pests. These farmers identified white stem borer and rice leaf folder as the most encountered insect pests on the local rice crops. Due to these insect pests, rice production became constrained producing low income for the farmers. Pesticide application was perceived to be effective (73%) but not efficient in controlling insects. Moreover, farmers recognized the negative effects of pesticide applications in the environment (76%). However, in spite of these expensive pest control strategies, local farmers still agreed (83%) to apply these methods to increase rice production and their income. With the advantage of using pesticides to boost production over the harm it can cause, farmers would not agree to stop (39%) or still are undecided (23%) to reduce pesticide application. Thus, efficient, safe, low cost pest control strategies are needed to reduce reliance of farmers to pesticides and to improve agricultural production and food security of smallholder farmers in the Philippines.
    Keywords: Crop damage, Farmer’s attitude, Pesticide, Production constraints, Rice farming, Socioeconomic status
  • B. Rahimi, A. Ebrahimi *, N. Mansouri, N. Hosseini Pages 43-60
    In this study, the photocatalytic degradation of azo-dye acid orange 10 was investigated using titanium dioxide catalyst suspension, irradiation with ultraviolet-C lamp and bismuth vanadate under visible light of light-emitting diode lamp. Response surface methodology was successfully employed to optimize the treatment of acid orange 10 dye and assess the interactive terms of four factors. The characteristics of catalysts were determined by field emission scanning electron microscopes, X-ray diffraction and Fourier transform infrared spectroscopy. The optimum values of initial dye concentration, initial pH, irradiation time and catalyst dose were found 11.889 mg/L, 4.592, 12.87 min, and 0.178 g/100 mL for ultraviolet/titanium dioxide process, respectively, and 10.919 mg/L, 3.231, 320.26 min and 0.239 g/100 mL for visible/bismuth vanadate process, respectively. The removal efficiencies obtained for acid orange 10 were 100% and 36.93% after selecting the optimized operational parameters achieved for titanium dioxide and bismuth vanadate, respectively. The highest efficiency was achieved by the use of ultraviolet/titanium dioxide system, while a low acid orange 10 removal efficiency was obtained for the synthesized bismuth vanadate using the co-precipitation method. Thus, it seems necessary to increase the photocatalytic activity of bismuth vanadate in combination with titanium dioxide to remove acid orange 10 dye in subsequent studies.
    Keywords: Acid orange 10 (AO10), azo dye, Bismuth vanadate (BiVO4), Photocatalytic degradation, Titanium dioxide (TiO2), visible
  • Sh.F. Abd El, Kader, G.A. El, Chaghaby *, G.M. Khalafalla, R.I. Refae, H.M. Elshishtawy Pages 61-70
    Congo red is a synthetic azo-dye dye with many industrial applications. The effluents containing azo dyes are causing several environmental hazards and thus should be treated prior to their discharge. The present work investigates the possible use of a novel microbial consortium from sheep compost for the decolorization of Congo red dye. The effect of different parameters including contact time, dye concentration and inoculum concentration on dye decolorization were investigated. The kinetic of dye decolorization was also assessed and the biodegradation of the dye was confirmed by different techniques. The results showed that the microbial consortium decolorized about 98% of Congo red (500 mg/L) after 24h. The efficiency of the decolorization decreased from 95% to 62% when the dye concentration increased from 100 to 500mg/L. Also, it was noticed that 75% of Congo red (25 mg/L) was decolorized at an inoculum rate of 2.5%. The kinetic results suggested that the decolorization of Congo red by the studied consortium follows the first order kinetic model. Also the maximum substrate consumption rate (Vmax) according to Michaelis- Menten model was found to be 19.30 mg/h/L and the decolorization rate constant (Km) was 116.93 mg/L. The biodegradation of Congo red was further confirmed by HPLC and GC-Ms analysis which revealed the presence of some spectral differences between the untreated dye sample and the treated one. In conclusion, the results of the present work suggest that microbial consortium from sheep compost could have potential application for bioremediation of industrial effluents containing Congo red dye.
    Keywords: Azo dyes, Biodecolorization, Biodegradation, Congo red (CR), Kinetics
  • R.C.C. Puno*, G.R. Puno , B.A.M. Talisay Pages 71-82
    Predicting the impact of land cover and climate change on hydrologic responses using modeling tools are essential in understanding the movement and pattern of hydrologic processes within the watershed. The paper provided potential implications of land conversions and climate change scenarios on the hydrologic processes of Muleta watershed using soil and water assessment tool model. Model inputs used include interferometric synthetic aperture radar-digital elevation model, 2016 land cover map, soil map, meteorological and hydrologic data. The model was calibrated using appropriate statistical parameters (R2=0.80, NS=0.80 and RSR=0.45). Model validation using observed streamflow with the same statistical parameters (R2 = 0.79, NS = 0.67 and RSR = 0.57) showed that the result was statistically acceptable. The model provided potential implications of land conversions and climate change adversely affecting hydrologic processes of critical watersheds. Climate change projections with a 13% decrease in rainfall directly influenced the decrease in hydrologic processes. Meanwhile, urbanization had influenced the increase in surface runoff, evapotranspiration, and baseflow. The increase of forest vegetation resulted in a minimal decrease in baseflow and surface runoff. The watershed hydrologic processes were influenced by changes in land cover and climate. Results of this study are useful by the localities and policy makers in coming up with a more informed decision relative to the issues and concern on hydrological responses in the uplands.
    Keywords: Hydrologic model, Hydrologic processes, Scenario analysis, Streamflow, Watershed modeling
  • B. Gwada *, G. Ogendi, S.M. Makindi, S. Trott Pages 83-94
    Among the emerging environmental issues within Sub-Saharan Africa is the haphazard disposal of plastic waste, some of which end up downstream in the marine environment leading to negative effects. Notably there have been cases of humpback whales getting entangled in ‘ghost’ fishing nets, and endangered turtles ingesting plastic wastes in Watamu beach in Kenya. The aim of the current study was to assess the composition and management of plastic waste discarded by households in Watamu ward. Stratified random sampling was used to collect data from households in four sub-locations within Watamu ward. Data were analysed using descriptive and inferential statistics (the Freeman-Halton extension of the Fisher’s Exact test). The composition of plastics usually discarded as waste by households in order of dominance were low density polyethylene, polyethylene terephthalate, high density polyethylene and polypropylene (FH=37.959, p = 0.000). From the results, only 0.7% of respondents recycled their plastic waste. The most preferred disposal method of household plastic waste was open dumpsites (61.4%) followed by burning (12.9%) and discards (6.4%). Majority of respondents (93.6%), re-use some plastic containers for food, water, and oil storage. There was a significant difference in terms of how the respondents re-used their plastic waste in the four sub-locations (FH=36.437, p=0.005). In conclusion, the current plastic waste disposal methods at Watamu are not environmentally friendly and recycling is still at a smaller scale despite its potential to generate income and clean the environment, and promote ecosystem services and human wellbeing.
    Keywords: Plastic composition, Plastic waste, Recycling, Reuse, Waste management
  • J.L. Ogania *, G.R. Puno, M.B.T. Alivio , J.M.G. Taylaran Pages 95-106
    Flooding is one of the most devastating natural disasters occurring annually in the Philippines. A call for a solution for this malady is very challenging as well as crucial to be addressed. Mapping flood hazard is an effective tool in determining the extent and depth of floods associated with hazard level in specified areas that need to be prioritized during flood occurrences. Precedent to the production of maps is the utilization of reliable and accurate topographic data. In the present study, the performance of 3 digital elevation models having different resolution was evaluated with the aid of flood modeling software such as hydrologic engineering centre-hydrologic modeling system and hydrologic engineering centre-river analysis system. The two-dimensional models were processed using three different digital elevation models, captured through light detection and ranging, interferometric synthetic aperture radar, and synthetic aperture radar technologies, to simulate and compare the flood inundation of 5-, 25- 100-year return periods. The accuracy of the generated flood maps was carried out using statistical analysis tools - Overall accuracy, F-measure and root-mean-square-error. Results reveal that using light detection and ranging–digital elevation model, the overall accuracy of the flood map is 82.5% with a fitness of 0.5333 to ground-truth data and an error of 0.32 meter in simulating flood depth which implies a promising performance of the model compared to other data sources. Thus, higher resolution digital elevation model generates more accurate flood hazard maps while coarser resolution over-predicts the flood extent.
    Keywords: Disaster, Geographic information system (GIS), Hydrologic engineering centre-hydrologic modeling system (HEC-HMS), Inundation, River analysis system (RAS)
  • S. Sadjad Mehdizadeh* , S. Badaruddin, S. Khatibi Pages 107-118
    In this study, abstraction, desalination and recharge method and SEAWAT numerical model are used to investigate seawater intrusion repulsion in a hypothetical two-dimensional coastal aquifer to understand the relation of seawater intrusion with abstraction, desalination and recharge parameters (i.e. abstraction/recharge rate, wells distance and depth). Abstraction, desalination and recharge consists of abstraction and desalination of brackish water and recharge of desalinated water. The results of different defined scenarios showed that increase of recharge rate has a significant effect on the seawater intrusion mitigation (e.g. more than 80% variation in saline water volume) while the increase of abstraction rate does not have specific impact on seawater recession (e.g. less than 3% variation in toe position). The method efficiency in reducing seawater intrusion is increased when freshwater is recharged by well at outside of saltwater wedge and close to its toe position. Moreover, it is shown that the abstraction, desalination and recharge performance has slightly improved when the recharge and extraction wells are placed deeper into aquifer and close to aquifer bottom (almost 15% for all characteristics of salt wedge). Ultimately, dilution of saline water with recharged freshwater will widen the mixing zone but as salt wedge recedes toward the sea simultaneously, the mixing zone thickness cannot follow the steady reduction trend.
    Keywords: Abstraction, desalination, recharge (ADR), Controlling method, Mixing zone, Seawater intrusion (SWI), Toe position
  • A. Cruz, Salomn *, E. Ros, Valdovinos, F. Pola, Albores, S. Lagunas, Rivera , R. Meza, Gordillo, V.M. Ruz, Valdiviezo, K.C. Cruz, Salomn Pages 119-138
    The expanded granular sludge bed bioreactor appears today as a cheap, robust and more popular technology because it operates using a fluidized bed, which allows increasing in organic load and in cell retention times, generating higher treatment efficiencies (up to 95 %) and renewable energy (i.e., biogas, biomethane, and biohydrogen). Nevertheless, the efficiency of this bioreactor mainly depends on the operating conditions. Thus, the content presented in this review paper focuses on the analysis of the operating conditions and performance of expanded granular sludge bed bioreactor for treating different types of industrial, agro-industrial and domestic wastewaters (e.g., agro-food, beverage, alcohol distillery, tannery, slaughterhouse, chemical, pharmaceutical, municipal sewage, among others). Because of this reason, this study aimed to analyze the operating conditions and type of substrate, which has been used in these bioreactors to improve future research to wastewater treatment and renewable energy production. According to the review, it is concluded that the EGSB bioreactor is a novel sustainable alternative to treat different types of wastewaters and consequently change the paradigm of wastewater management from "treatment and disposal" to "beneficial use" as well as "profitable effort".
    Keywords: Anaerobic EGSB bioreactor, Hydrodynamics, Mathematical model, Operating conditions, Renewable energy production, Wastewater treatment