دانلود رایگان مقاله انگلیسی ارزیابی اثرات فاضلاب کنونی و آینده صنایع رنگرزی در بنگلادش - الزویر 2018

Abstract

The textile sector has been an important part of Bangladesh’s (BD) economy over the past few decades. In Bangladesh, the textile sector currently has an export value of nearly 28 billion USD per year which contributes about 82% of the country’s total export earnings. It is projected that the annual ready-made garment (RMG) export value will be about 50 billion USD per year by 2021. However, the growth of Bangladeshi RMG sector is associated with different environmental issues, mostly caused by wastewater generated by textile industries. Textile industries consume high volumes of water per unit fabric for processing, which cause depletion of ground water levels at a high rate. In addition, in many cases textile effluents are discharged into rivers or wetlands without proper treatment. Untreated textile effluent can contaminate groundwater and waterbodies, reduce dissolved oxygen in water and affect aquatic ecosystems which may indirectly cause climate change. Improving conventional technology, adopting cleaner production (CP) options, the reusing and recycling of treated water may reduce water consumption, effluent volume and water stresses, and may help preserving aquatic ecosystems. However, additional investments, lack of technological knowhow, and awareness are factors limiting the adoption of cleaner production options. In order to take effective measures for future improvement it is important to develop a nationwide wastewater impact tracking system. In this study, a material balance approach has been developed to characterize the trend of pollution impacts (2011-2021) associated with the textile dyeing industries of Bangladesh. It is estimated that in 2016 textile industries in Bangladesh produced about 1.80 million metric tons of fabric, which generated around 217 million m3 of wastewater (2016) containing a wide range of pollutants. It is projected that wastewater production will reach 349 million m3 by 2021 if the textile industries continue using conventional dyeing practices. Gradual adoption of improved technology and cleaner production options could reduce wastewater volume by around 23% by 2021. This projection will help policy makers to take necessary mitigation measures for treatment and pollution management. This analysis will also provide a baseline scenario and open new opportunities for textile engineers and environmentalists to develop innovative technologies for textile dyeing and effluent treatment.

5. sonclusions

Textile production is the largest manufacturing sector in Bangladesh. The growth in this sector, and other small and medium scale enterprises, undoubtedly has a positive effect on national economic development; however, there are also environmental concerns. Effluent from textile industries is a major source of environmental pollution. In this study, the past trend (2011-2016) and future projection (2017-2021) of pollution impacts associated with the Bangladesh textile dyeing industry was developed by analyzing yearly RMG export data, RMG production growth rate, and pollution loads for textile dyeing industries. It is estimated that by 2021, BD textile industries will produce around 2.9 million metric tons of fabric, which will generate about 349 million m3 of wastewater. Considering conventional key performance indicator (KPI), 349 million m3 of wastewater will contain about 1,469,641 metric ton of TDS, 49,442 metric ton of TSS, 175,252 metric ton of BOD and 519,342 metric ton of COD. It is important to understand the effects of the TDS, BOD, and COD on the biological diversity of local rivers and wetlands; and this requires systematic research. To reduce water extraction, water footprint and water stress, it is vital to treat textile effluents, implement cleaner production options, introduce waterless dyeing technologies, and reuse the treated water. This study will serve as a baseline to help the Government, funding agencies, industry management and technologists to analyze the wastewater impact of increased textile production, and to develop environment friendly dyeing practices and technologies.