River pollution in Bangladesh
Causes and possible solutions
PART-2Industrial Pollution: According to the Ministry of Environment and Forests, the water of the rivers surrounding Dhaka city where wastewater is discharged without adequate treatment is highly polluted. The rivers have been characterized as ecologically critical areas. Few textile factories in Bangladesh maintain wastewater treatment processes at the necessary level to meet discharge standards. A World Bank study said four major rivers near Dhaka--the Buriganga, Shitalakhya, Turag and Balu--receive 1.5 million cubic meters of waste water every day from 7,000 industrial units in surrounding areas and another 0.5 million cubic meters from other sources.
Everyday approximately 700 tanneries of Dhaka city are discharging about 16,000 cubic meters of toxic wastes. The Department of Environment (DOE) has listed 1,176 factories that cause pollution throughout the country.
A feature story by the World Bank in February 2017, "There are 718 washing, dyeing and finishing factories discharging wastewater to the rivers in Dhaka. And according to the International Finance Corporation's (IFC) best estimates this is generating as much as 200 metric tons of wastewater per tons of fabric." Despite being surrounded by four rivers, Dhaka's water supply to its 18 million residents is being threatened by the extremely high levels of pollution.
A study by Bangladesh Water Integrity Network (BAWIN) water is used extensively throughout textile processing, but it is not used efficiently. Average Bangladeshi textile production consumes 200-250 litres of water per kilogram (kg) of fabric production, nearly five times more than international best practice. The industry discharges 12.7-13.5 million of wastewater annually, representing 85-90 per cent of the groundwater it extracts for fabric processing. Overall, 20 per cent of freshwater pollution comes from textile treatment and dyeing.
According to the World Wildlife Fund (WWF) it can take up to 2,700 litters to produce the cotton needed to make a single T-shirt. Toxic chemicals can be discharged into water bodies from the textile dying process when appropriate effluent treatment measures are not taken. This not only affects the water bodies, but also has long-term implications on public health, food production, and the environment.
The International Finance Corporation (IFC) states that the industry consumes 1,500 billion litres of groundwater annually, a remarkable five times larger than the best practice benchmark. That is equivalent to the water needs of 800,000 people annually. This results in Dhaka's water level decreasing by 2.5 percent every year and may result in long-term groundwater depletion.
Oil pollution: River water gets contaminated because of oil spilled from boats and tankers while travelling around. The spilled oil does not break up in water and structures. In Bangladesh, mixing of oil in the river water is one of the reasons of river water pollution.
Swage and solid waste effluent: The management of sewage in Dhaka water supply with authorities admitting that most domestic and industrial waste heads to the four rivers--Buriganga, Turag, Sitalakkhya, Balu and wetlands around the city. Buriganga, beside which Dhaka's first water treatment plant was set up in 1875 by Nawab Khaja Abdul Ghani, receives the most waste. According to Bazlur Rahman, an engineer at the housing and public works ministry, there are at least 60 discharge points that release storm water combined with domestic and industrial effluents into the rivers.
The careless disposal of untreated wastewater and solid waste into the rivers and its water system significantly contributes to the poor quality of the water. The water quality not only depends on the water itself but also depends on the toxic substances into the other ecosystem. This not only creates a crisis for clean water but also results in agriculture lands becoming inundated with toxins, fish stocks dying, and people suffering from health problems.
Water plays an important role in the economy; ecosystem, natural resources, agriculture, fisheries and navigation are all dependent on sustainable use of water resources. Deteriorating water quality has become a great concern, linked to population growth, untreated discharge of sewage, unplanned urbanization and industrialization.
Dhaka city dwellers generate at least 18 lakh cubic meters of sewage daily, says Professor of BUET Mr Mujibur. Most of this huge quantity of waste remain untreated and is dumped into different rivers, canals and water-bodies, he says. The lone waste treatment plant at Pagla in Narayanganj has a capacity of treating 1.20 lakh cubic metre of sewage but it can give only one-third its output due to clogged sewage pipes.
The indiscriminate discharge of solid waste, domestic and hospital sewage are the major source of water pollution in Bangladesh. About 4,000 to 4,500 tons of solid wastes are generated daily and only half of the generated wastes are disposed of in low lying areas or into river water. These solid wastes are associated with the problems of littering on roads, spilling around the bins, clogging of drains, indiscriminate dumping on vacant plots and cause serious environmental pollution. More than 500 hospitals and clinics of Dhaka city generate and release hazardous and toxic wastes without any treatment.
According to the WASA in the absence of modern treatment facilities, a cringe-worthy 80 percent of the capital's sewage goes directly into the river Buriganga, Turag and Balu Rivers every day. At present operates the Sewerage Treatment Plant (STP) in the country at Pagla in Narayanganj which treats 20 per cent of the city waste.
As per 1984 building construction rules dictate that each owner should set up septic tanks or soak pits and manage the sewage on their own. But to avoid cleaning costs, most people connect the pits to the storm drains. Some do not even bother setting up tanks or pits and dump the faces directly to the storm drains and then sewage are dumping into river.
Lacking sanitation represents a genuine natural risk of water pollution in Bangladesh. Dhaka Water and Sewerage Authority (DWASA) can serve just 15 to 20 per cent of city the city dweller. Without the sanitation and infrastructural administrations, 40 per cent septic tank and douse pit, 15 per cent utilizing pit latrines and 30 per cent utilizing open toilets. The sewage is for the most part discharged into low-lying territories and the untreated water causing incredible risks to nature.
The writer is correspondent, American International News Service, columnist and conservator, Wildlife and environment. He can be reached at: [email protected]