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.
