Industrial pollution is an area of growing environmental concern in Bangladesh. The country still has a relatively small industrial base (including manufacturing, construction, mining and utilities) contributing about 20% of GDP (1996-97). The manufacturing sub-sector accounts for about half of this contribution and it grew at a rate of 5.04% between 1972 and 1992. The growth rates of some of the important sub-sectors are shown in Figure 1.1 (Bhattacharya et al., 1995). With the growth of the ready-made garments sector, the textile sector is also growing at a high rate in recent years.

Treatment of industrial waste and effluent has so far been considered a low priority, because policy planners had a feeling of complacency that industrial pollution is still at a very low level. Due to lack of awareness as well as the absence of strong punitive actions, the practice of circulating waste and effluent into water bodies including ponds, canals, creeks and rivers still remains widespread. The serious public health hazards they create are to some extent minimized as the waste and effluents are mostly flushed out into the sea during the rainy season. But excessive localized pollution is already threatening the sustainability of the resource base and having effects on the health of people, most of who are affected or unaware or hardly have any other choices.

With the Earth Summit in Rio and the Kyoto Protocol in Japan, the 1990s have been a significant decade in reshaping conventional development thinking into sustainable development. This new trend guides us to clean up existing industries and develop new ones with minimum environmental impacts. In the process, development of recycling systems, waste exchange and industrial ecology will replace the linear industrial processes with a more circulatory structure.

By having a small industrial base Bangladesh is in an advantageous position for getting a head start in developing clean and sustainable industries. The wise approach is to learn from the mistakes of the already industrialized countries and take proactive measures in planning and managing the industrial sector. This paper summarizes the status quo of industrial development in Bangladesh, categorizes the existing industries, estimates the total load of various pollutants, reviews the legal framework and makes policy recommendations that will help reduce the impacts of industrial pollution in future.

The major polluting industries such as tanneries, pulp and paper, sugar, fertilizer, pharmaceuticals, metal, and chemical industries are mostly located in and around the major cities. Some of these are also located on the banks of major rivers and lakes.

The major industrial locations of the country are concentrated in three metropolitan areas:

i. Dhaka, which includes Tejgaon, Hazaribagh, Demra, Tongi, Savar and Narayangonj. The DOE has identified 450 polluting industries in Dhaka divisions; of these only 21 have taken environmental clearance from DOE. The most polluting hot-spot of Dhaka is Hazaribagh where the tanneries are located. This is separately discussed in the Case Studies section of this paper. Another unique group consists of the factories located in old Dhaka. This area is examined in a Case Study. Most of the liquid wastes created by the industries in Dhaka are dumped directly or indirectly into the rivers Buriganga, Balu and Sitalakhya.

ii. Khulna, which includes Shiromoni, Kalishpur and Rupsha. Some 300 industries are located in and around Khulna City currently discharge huge amount of liquid waste into the river Bhairab These include Khulna Newsprint Mill, a large number of jute mills including Crescent Jute Mills Company, many match factories, textile mills and Bangladesh Cable Shilpa Sangstha – all are causing severe water pollution of the Bhairab River. These pollutants may be contributing to the “top dying” disease of the tress in the Sunderbans in addition to causing serious damage to both freshwater and marine ecosystems.

iii. Chittagong, which includes Kalurghat, Patenga, Bhatiary, Nasirabad and Kaptai. The main polluters are the pulp and paper, fertilizer and petroleum/refineries industries. Most of the industries are located on the banks of the Karnafuli River and the Kaptai Lake. Another group unique to Chittagong is the ship building/wrecking industry. This sub-sector (included in the broadly defined metal industries sector) contributes a lot of marine oil pollution. The other source of oil pollution are the ships and boats using the port and the outer anchorage area of Chittagong. Ballast and bilge waters from oil tankers and ships anchored in the port should only be emptied at installations where the oil can be separated and recycled. This is obligatory in many countries but in Chittagong, ships directly discharge their waste oil-water mixtures into the Bay of Bengal.

iv. Bogra is a rapidly growing industrial center in the northwestern part of the country where many of the machine tools and agro-based industries are located.

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Water Pollutants

Biological Oxygen Demand (BOD): BOD is defined as the amount of oxygen needed by aerobic decomposers to breakdown the organic materials in a given volume of water at a certain temperature over a specified time period. BOD is caused by organic water pollutants that are oxidized by naturally-occurring micro-organisms. This 'biological oxygen demand' removes dissolved oxygen from the water and can seriously damage some fish species which have adapted to the previous dissolved oxygen level. Low levels of dissolved oxygen may enable disease causing pathogens to survive longer in water. Organic water pollutants can also accelerate the growth of algae, which will crowd out other plant species. The eventual death and decomposition of the algae is another source of oxygen depletion as well as noxious smells and unsightly scum. The most common measure for BOD is the amount of oxygen used by micro-organisms to oxidize the organic waste in a standard sample of pollutant during a five-day period (5-day BOD)

Suspended Solids (SS): Small particles of non-organic, non-toxic solids suspended in waste water will settle as sludge blankets in calm-water areas of streams and lakes. This can suffocate plant life and purifying micro-organisms, causing serious damage to aquatic ecosystems. The loss of purifying micro-organisms enables pathogens to live longer, raising the risk of disease. When organic solids are part of the sludge, their progressive decomposition will also deplete oxygen in the water and generate noxious gases.

Toxic Chemicals: Many chemicals in industrial emissions are poisonous to humans. These chemicals affect humans through direct contact or through inhalation and intake as food. Humans can ingest severely damaging or fatal quantities through repeated exposure, or by consuming plants or animals in which these compounds have accumulated. Toxic chemicals may cause damage to internal organs and neurological functions; can result in reproductive problems and birth defects; and can be carcinogenic. Quantities and length of exposure necessary to cause these effects vary widely. Benzene and asbestos are known carcinogens linked to leukaemia and lung cancer. Common toxic chemicals include residues of pesticides and a very large group of organic chemicals that include benzene, toluene, zylene, chloroethane and chloromethane.

Bio-accumulative Metals: In bioaccumulation, relatively low concentrations of contaminants in air, water, soil and plants become far more concentrated further up the food chain. Some metals can be converted to organic forms by bacteria, increasing the risk that they will enter the food chain. Bio-accumulative metals are particularly dangerous because they are dissipated very slowly by natural systems. They may cause both mental and physical birth defects. Metals can also become rapidly oxidized and converted to soluble form when sediment is exposed to oxygen. Some of the metals which are commonly measured and particularly dangerous are mercury, lead, arsenic, chromium, nickel, copper, zinc and cadmium.

Emission to water

Emission to water was estimated in terms of BOD and TSS. The highest BOD contributor is the pulp and paper sector, followed by the food industries. As before, sugar mills and distilleries in the food sector cause most of the emissions. The dairy sub-sector has a very high BOD emission factor but at this point due to the small size of the industry, it is not a major BOD contributor. This may change in future. Collectively, pulp and paper, and food emits 93% of the total BOD load.

In terms of TSS emission, pulp and paper tops the list, followed by pharmaceuticals and metal industries. Both ferrous and non-ferrous industries have high TSS emission factors. Other high potential TSS emitters are fertilizer factories and jewelleries. Total contribution of the jewelleries is small due to small size of the industry. Its contribution is likely to be dispersed all over the country with the largest concentration in the older part of Dhaka.

Percent contribution of the major water pollutants are shown in Figure 1.

It is not surprising that the metal industry is the number one polluter of toxic metals that can cause severe health damage through direct contact and bio-accumulation. Other major polluters are the cement factories, tanneries and agrochemicals (pesticides in particular). Together, these sectors contribute nearly 75% of the total toxic metal emission. Although the estimates of total toxic metal include emissions to all media (air, water and land), most sectors emit 90% to 95% of the total load to land. The only notable exception is the pulp and paper sector, which emits about 67% of the total load to land and 30% to water. Emission to air is small for most of the sectors. The only two sectors with small but noticeable emission to air are the petroleum/refineries and the paints/varnish/lacquer.
 

The number one toxic chemicals polluter is the tanneries and leather industry, followed by pulp and paper, pharmaceuticals, fertilizer/pesticides and industrial chemicals. In most cases, the chemicals are disposed on land as part of the solid waste, parts of which are then collected and recycled. Exceptions are the pulp and paper and cement factories – these emit most of the chemical to air. Direct emission to water appears to be small – the two significant ones are 18% by the pulp and paper, and 10% by the industrial chemicals. However, it is quite likely that a significant part of the land pollution eventually ends up in water through direct runoff and seepage. Unfortunately, no information is available on the ultimate fate of these toxic chemicals.


The emission loads to water are shown in the Figure. The total BOD load is likely to increase due to the growth of agro-industries, pulp and paper and industrial chemicals sub-sectors. These also contribute to emission of TSS. However, the metal based industries, that include iron and still mills, foundries and re-rolling factories, had undergone a major drop in the number of workers employed during the 80’s that is responsible for the declining trend of TSS emission. Whether this trend was reverting in the 90’s has not been determined, and therefore, this projection should be treated carefully.

Source: Islam Faisal, Rumi Shammin, Juhaina Junaid, Industrial Pollution in Bangladesh, The World Bank.