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A long-term (1948 to 2012) trend of precipitation (annual, pre-monsoon, monsoon, and post-monsoon seasons) in Bangladesh was analyzed in different regions using both parametric and nonparametric approaches. Moreover, the possible teleconnections of precipitation (annual and monsoon) variability with El Niño/Southern Oscillation (ENSO) episode and Indian Ocean Dipole (IOD) were investigated using both average and individual (both positive and negative) values of ENSO index and IOD. Our findings suggested that for annual precipitation, a significant increasing monotonic trend was found in whole Bangladesh (4.87 mm/year), its western region (5.82 mm/year) including Rangpur (9.41 mm/year) and Khulna (4.95 mm/year), and Sylhet (10.12 mm/year) and Barisal (6.94 mm/year) from eastern region. In pre-monsoon, only Rangpur (2.88 mm/year) showed significant increasing trend, while in monsoon, whole Bangladesh (3.04 mm/year), Sylhet (7.17 mm/year), and Barisal (6.94 mm/year) showed similar trend. In post-monsoon, there was no significant trend. Our results also revealed that the precipitation (annual or monsoon) of whole Bangladesh and almost all of the spatial regions did not show any significant correlation with ENSO events, whereas the average IOD values showed significant correlation only in monsoon precipitation of western region. The individual positive IODs showed significant correlation in whole Bangladesh, western region, and its two divisions (Rajshahi and Khulna). So, in the context of Bangladesh climate, IOD has the more teleconnection to precipitation than that of ENSO. Our findings indicate that the co-occurrence of ENSO and IOD events may suppress their influence on each other. [ABSTRACT FROM AUTHOR]

The purpose of this research is to evaluate the intent of empty fruit bunches of palm oil (EFBpalm oil) to catalytic gasification of wood produced charcoal (Woodcharcoal) in order to notify the large-scale application of Woodcharcoal as a possible gasification feedstock. In this study, co-catalyst of bismuth oxide (Bi2O3) was also used to obtain syngas. The raw samples were characterized by proximate and ultimate analyses, X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) analyses. The produced syngas was analyzed by online portable gas analyzer and gas chromatography-thermal conductivity detector (GC-TCD). The syngas composition of H2 increased from 3.91 to 4.70% (increased 20.20%), CO increased from 5.73 to 6.30% (increased 10.53%), whereas CO2 decreased from 20.60 to 12.67% (decreased 38.50%) and CH4 concentration increased insignificantly from 0.35 to 0.37% (increased 5.7%) which was happened due to the use of WoodCharcoal and Bi2O3 with EFBpalm oil during gasification. According to the findings, carbon is abundant in WoodCharcoal, which may considerably boost the gasification reactivity with Bi2O3. The yield of syngas (H2 and CO) increased when WoodCharcoal and Bi2O3 were used instead of single EFBppo gasification, indicating that catalyst (WoodCharcoal) and co-catalyst (Bi2O3) have a high potential for thermal decomposition and dehydrogenation of volatile matter. Therefore, catalytic gasification of empty palm fruit bunches will be the prospective energy sources for the production of syngas with the utilization of WoodCharcoal and Bi2O3. [ABSTRACT FROM AUTHOR]

This study is aimed to apply dry anaerobic digestion (DAD) for methane (CH4) enriched biogas production from unsorted organic municipal solid waste (MSW). Cumulative biogas production was monitored for 35 days of operation in batch digesters at fixed feedstock to inoculum (F/I) ratio 2. Anaerobic sludge (AS) and cow manure (CM) were used as inoculum in single and mixed modes. Several process parameters such as inoculum flow pattern (single layer, multilayer, and spiral), digestion temperature (25 to 40 °C), inoculation modes (single and mixed mode), and inoculation proportion (AS:CM = 1:1, 1:2, 1:3, and 2:1) were investigated to determine the optimum DAD conditions to maximize the CH4 laden biogas yield. The study of inoculum flow pattern showed that digester with multilayer inoculum configuration generated the maximum 555 mL cumulative biogas with the production rate of 195 mL/day (at 25 °C). Biogas production rate and cumulative biogas production were found to increase with a rise in temperature and the maximum values of 380 mL/day and 1515 mL respectively were observed at 37 °C. The mixed mode of inoculation containing AS and CM augmented the biogas yield at previously optimized conditions. Final results showed that digester with multilayer inoculum flow pattern at 37 °C produced 1850 mL cumulative biogas with 1256.58 mL CH4/kg volatile solid (VS) when the mixed inoculum was used at the AS:CM—1:2 ratio. Biogas production with this significant amount of CH4 justifies the use of the DAD process for energy (biogas) generation from widely available biomass feedstock (MSW), offering various advantages to the environment. [ABSTRACT FROM AUTHOR]