Characteristics of major industrial liquid pollutions in Bangladesh

Abstract

Bangladesh is promoting rapid industrial development and on the other hand industries contribute to serious pollution problems, since a large number of industries discharge their wastes, including potentially toxic substances, without treatment directly into the environment. The characterisation of this raw waste is an essential component of the overall planning for effective and economical methods of industrial liquid waste pollution control. The treatment units for different types of industries can be designed with due consideration to the varying nature of industrial waste characteristics. Therefore, characterisation of industrial liquid wastes prior to a treatment plant design is very important. On the basis of pollution effect on the environment, the major industries in Bangladesh are categorised as textile, tannery, pharmaceutical, fertiliser, paper and pulp, vegetable oil, sugar, cement, steel, paint and chemical industry. Most of the industries under these categories do not have any type of treatment facilities and they routinely discharge their raw wastes ; which contains various toxic and hazardous substances directly or through the local storm drainage system to nearby khal, lake or river. To quantify the characteristics of major industrial liquid pollutants in Bangladesh, the important parameters those have been taken under consideration are pH, BOD5, COD, SS, TS, inorganic substances (Nitrogen, Phosphorous, Chlorides), sulphate, sulphide, heavy metals (Cu, Zn, Hg, Cr, Pb), colour and turbidity. The study was conducted through collecting different industrial effluent test results from the Environmental Engineering Laboratory, BUET and then analysed by using computer software (EXCEL). The study reveals that in most cases, the concentration of these parameters exceed the respective EQS for discharge into a surface water body. Since river water is largely used for drinking, washing, irrigation and fisheries purposes; serious adverse economic, environmental and human health effects occur due to the discharge of industrial liquid pollutants in surface water bodies. A wide variation of the range of characteristics of different parameters has been observed in the same categorised industries. The characteristics of industrial liquid wastes in our country vary from place to place and depend on various factors like raw materials used, manufacturing process, condition of machinery, water supply position, weather condition of the locality etc. With due Consideration of these factors and from laboratory analyses of wastes a general characteristics of major industrial liquid pollutants has been proposed in this study. Results of this study suggest that the eftluents from different categorised industries need to be properly treated before discharge into a surface water body.