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The CO2 emission is more than 36 billion tons per year in global scale. As carbon dioxide emission raises global temperature by trapping solar energy in the atmosphere, research is ongoing to facilitate the capture of CO2 with high efficiency. While CO2 footprint of Bangladesh is relatively low, with upcoming coal-based power plants (>17000 MW) in the next decade, fossil CO2 emission will increase significantly. To understand the underlying benefit of CO2 capture process, cradle-to-gate life cycle impact assessment (LCIA) of the power plants using fossil sources (e.g. natural gas, coal) can provide an in-depth insight. This paper aims to conduct life cycle impact assessment on natural gas and coal (sub critical and supercritical) fired power plants with and without CO2 capture facility for comparison of overall impact on the environment. An open source software titled OpenLCA was used to carry out LCIA and study different impact parameters (i.e. green-house gas emission, toxicity and ozone layer depletion). It was found that the CO2 emission from super-critical pulverized coal (SCPC) and subcritical pulverized coal (Sub-PC) fired power plants could be brought down by more than 80% using CO2 capture facility. Along with capture, it is equally important to ensure proper sinks for this captured CO2. As Bangladesh has no dedicated geological reservoir for CO2 storage, potential sink for captured CO2 could be immediate utilization after capture. This paper also presents preliminary results on utilizing CO2 through mineralization during preparation of alternative admixture and construction materials. Due to the ever-growing real-estate sector of Bangladesh, there is great potential in capturing and utilizing CO2 through construction activities. [ABSTRACT FROM AUTHOR]

This paper presents evaluation of safety performance of three hazardous facilities based on current safety practice by measuring their safety weighted hazard indices (SWeHI) of multifarious units of chemical process and what can be done to avoid any potential accidents in context of Bangladesh. Assessing hazard potential over safety procuration is a key indicator of how well a facility is prepared to reduce its vulnerability. The risks associated with hazardous facilities are always greater in a country like Bangladesh as the safety issues are not often been prioritized by its key stakeholders. In recent years, there were number of deadly accidents occurred in the chemical industries and storage warehouses which resulted multiple fatalities and significant property damage. The accident could be avoided using proper safety protocols in those facilities. Here safety performance of three facilities was assessed based on survey data. These facilities deal with flammable, explosive and toxic chemicals. This index is on the basis of fire & explosions properties and toxic release properties as well as the safety precautions against it. It helps professionals to identify the overall hazard potential and distinguish less protected units from other well operated units. The paper features on an approximate yet workable assessment of risks at a low cost and based on the current safety practices. [ABSTRACT FROM AUTHOR]

Textile and apparel industries are the major role-players in the fast-growing economy of Bangladesh. However, the textile sector consumes a large amount of water for various wet processing operations. Currently 98% of the water used by local textile factories is groundwater, which is causing depletion of ground water levels at a high rate. Considering the gravity of groundwater crisis in future, Bangladesh Government and international brands and retailers are advocating local textile factories to reuse textile effluents and implement ZLD (zero liquid discharge) option in the upcoming years. However, it is a new concept for Bangladesh textile sector, and there is limited understanding regarding technical and economic issues associated to advanced treatment and reusing textile effluent. In this paper, a case study is presented to analyse the application of advanced membrane treatment of conventional ETP (effluent treatment plant) treated water of a denim washing factory. The corresponding technical and economic issues of water recycling and reusing were also analyzed. The selected denim washing factory runs a conventional biological effluent treatment plant (ETP) which satisfies the basic requirements of national and international standards. For advanced treatment, a mobile setup of ultrafiltration (UF) and reverse osmosis (RO) unit was used at factory premises to further treat ETP treated water. The advanced treatment was carried out for three different permeate to reject ratios to observe changes in the permeate and reject water quality. Capital expenditure and operational costs were also assessed to see the economic feasibility of the approach. This study will help local textile factories with real time data to understand the technical and economic issues associated to reusing textile wastewater as process water. [ABSTRACT FROM AUTHOR]

Fire accidents are very frequent and a major issue in Bangladesh in recent times. In this paper fire growth behavior in an apartment building is studied through a numerical analysis using Fire Dynamic Simulator (FDS). A model apartment with fixed combustibles was created using FDS. The fire growth characteristics were studied and heat release rate, the rise of temperature, toxic gas dispersion and human evacuation were assessed. The fire was generated using a burner function. Computational analysis results from those models were analyzed and discussed. The relationship of wind and ventilation effect with time helps to predict the fire growth behavior in different location of the apartment. Evacuation modeling was created to illustrate the effect of evacuation time and fractional effective dose (FED) for different types of agents. FED is the summation of toxic gas consumption which is important for safe evacuation. The results show that the ventilation effect releases the heat and makes the apartment less vulnerable. Elderly people took more time for total evacuation than other groups that related to FED percentage. The idea of critical door length is demonstrated for safe evacuation during fire emergencies. [ABSTRACT FROM AUTHOR]

Organic municipal solid waste (OMSW) - a potential energy source - is creating serious environmental hazards across Bangladesh, but it can be digested for biogas production to meet the ever-increasing energy demand of the country. The present study applied the dry anaerobic digestion (DAD) process for biogas production from OMSW with inoculum cow manure (CM) and anaerobic sludge (AS) in single and mixed modes. The performance of the DAD process was evaluated in batch digesters with a multilayer inoculum flow pattern maintained at the constant mesophilic condition of 37 °C. Firstly, CM and AS were studied individually, and later on, both of them were used together in different ratios (AS:CM = 1:1, 1:2, 1:3, and 2:1) to maximize the biogas yield from the DAD process. CM alone produced a total of 2.91 ml biogas/ g of biomass over 35 days of DAD while this yield was increased to 3.19 ml/g for mixed inoculum at the ratio of 1:3. These results imply that mixedmode inoculums would be a promising option in the DAD process for biogas production which will reduce both the energy scarcity and the burden of municipal solid waste (MSW) management [ABSTRACT FROM AUTHOR]

In this study occupational risk assessment in Readymade Garments (RMG), Textile and Ship Breaking Industries of Bangladesh was carried out utilizing accident database of Department of Inspection for Factories and Establishments (DIFE), Ministry of Labour and Employment. The study focused on the workplace incidents reported to DIFE from 2016-2018 in RMG, Textile and Ship Breaking industries of Bangladesh. The risk analysis was conducted based on severity and likelihood of events, the latter comprising: frequency of exposure to the hazard, duration of exposure to the hazard, probability of occurrence of a hazardous event, and technical and human possibility of avoiding or limiting the harm. To carry out the assessment, survey data including working time, accident frequency, cause of accident, nature of injury, use of personal protective equipment (PPE), health safety policy, first aid facility etc. were collected from DIFE. The risk scores and economic losses due to accidents in different years for each industry were estimated. The overall risk scores estimated for RMG and Textile industry were found to be higher than that for Ship Breaking industry. However, in Ship Breaking industry 41.3% of total incidents are of very high-risk, which is much higher than the percentage of such incidents in RMG or Textile industry. It was also found that the total compensation provided to the workers as reported to DIFE is 58.5% less of the estimated cost based on the fatality and type of injuries. [ABSTRACT FROM AUTHOR]

Split type room air conditioners (RACs) are very common nowadays. In Bangladesh, RAC manufacturers employ trial-error prototyping techniques in their design to increase the efficiency of RACs and the profitability of the plant. Computer modeling can be a great help to reduce the cost in the R&D stage to find the optimum design of RACs. In this study, modeling of heat transfer in the condenser of split type RACs employing the techniques of Computational Fluid Dynamics (CFD) was performed. To reduce the computational load the geometry was divided into small sections and geometric symmetries were also taken into account. For the simulation, the geometry and other relevant data were set in such a way so that they commensurate closely with real industrial data. An example data set for validation of simulation results were obtained from an AC manufacturer company, Elite Hitech Industries Ltd. The geometry was built using meshing techniques. Copper and aluminum were selected as materials for tubes and fins, respectively. R-22 was chosen as the refrigerant. Heat transfer and fluid flow were modeled using non-isothermal flow in a multi-physics environment. The main assumptions employed are laminar flow, extra coarse mesh size, constant air inlet temperature, perfect insulation between system and surroundings, and thin layer fins. The temperature distribution and heat transfer efficiency in the condenser, the impact of different refrigerant flow arrangements in the tubes have been studied in detail. This study leads to the finding of efficient refrigerant flow arrangements from the viewpoint of maximum heat transfer. [ABSTRACT FROM AUTHOR]

Municipal solid waste (MSW) is one of the top contributors in greenhouse gas (i.e. methane) emissions - particularly from landfill disposals. However, it could be a remarkable source of renewable energy. In Bangladesh, generation of municipal solid waste is at least 2.7 million tonne per year in the major cities, implying a heavy environmental burden. On the other hand, there are several coal-based power plants are in the pipeline to meet the increasing energy demand in Bangladesh with the potential of significant CO2 emission. To find a remedy to the above situation, a power plant using Integrated Gasification and Combustion Cycle (IGCC) technology with pre-combustion carbon capture is considered in this study. IGCC has the advantage of producing high quality syngas from a wide variety of feed and assists in the capture of CO2 at a lower cost while providing high electric efficiency. The power plant was simulated by commercial simulation packages (Aspen PLUS™ and Aspen HYSYS™) using MSW and bituminous coal (Indonesian) as a combined feed. With a feed rate of 1800 tonne per day, Syngas produced from an entrained flow type gasifier was then treated for CO2 removal using mono-ethanol amine (MEA) solvent after necessary shift in a high temperature shift reactor. About 91% efficiency was achieved in the shift reactor while the CO2 capture efficiency was varied for this study from 30% to 85%. Further parametric variation was studied by varying the moisture content of MSW and MSW to coal feed ratio. Through combustion of the H2 rich syngas in a gas turbine and subsequent steam cycle with reheat resulted in 125 MW of electricity at an efficiency of 28.95% while capturing 50% of the CO2 generated in the process for an MSW to Coal feed ratio of 1:1. With variation in moisture content especially during monsoon season, the plant efficiency could be affected remarkably. On the other hand, it was observed that the energy requirement varied from 6 to 8 MW for every 10% increase in CO2 capture quantity. Overall, by capturing 50% of the generated CO2, it is possible to reduce the emission of a same size ultra-supercritical coal-based power plant from about 700 kg CO2/MWh to about 360 kg of net CO2/MWh incorporating co-feeding and pre-combustion capture in an IGCC power plant. [ABSTRACT FROM AUTHOR]

With the rapid industrial growth, the need for renewable energy sources is rising fast. Being a developing country, Bangladesh aims towards industrial expansion, which is always followed by increased energy consumption. Considering the fact that fossil fuel is not sustainable and biomass sources are abundant and offer more versatility, the latter have become an attractive alternative to petroleum-based products. Moreover, utilization of biomass also seems promising because of biodegradability and lower greenhouse gas emissions, ensuring reduced environmental pollution, a grave concern with fossil-fuel technology. Biomass can range from agricultural byproducts to industrial and municipal wastes, however, very few biomass sources are currently being used in Bangladesh. Moreover, biomass can also be utilized to derive valuable chemicals, which are potential raw materials in several existing industries in Bangladesh. Despite having massive potential in Bangladesh, there haven't been organized studies on feedstock types, quantities, characterization and applications. Here we present an organized study to identify potential biomass sources and their available quantities. Considering specific waste fractions from varying sources, total amount of utilizable biomass resources have been calculated. A categorized proximate analysis data summary of varying biomass is also prepared that can be consulted in the future studies to calculate the theoretical possible production of energy as well as useful bio-chemicals based on efficient bio-processing techniques. This work is intended to benchmark the current efforts, and would add valuable information resources for the ongoing research towards achieving energy-sustainability and energy-security in Bangladesh. [ABSTRACT FROM AUTHOR]