Stink in the Water
A signboard outside the DND canal lists all the prohibited acts: don't through garbage into the water, don't pile garbage near the canal's bank, don't bathe, don't wash cloths etc. and states 'clean water is life'. The canal, meanwhile, is covered in water-hyacinth, a sure sign of high level of pollution.
Whenever, the dry season comes, millions of Dhaka residents are in utter misery because of contaminated water supplied by Dhaka Wasa. It's a common complaint that during the four months from January to April people get sticky water in many parts of the city, where treated water from Saidabad Water Treatment Plant (SWTP) and Chandnighat Water Treatment Plant (CWTP) is supplied. Of late, Dhaka Wasa has publicly apologised for supplying contaminated water and has blamed it on ongoing water pollution caused by industrial effluents for the contamination. Meanwhile, the city dwellers are still in the dark regarding when the crisis will be solved.
Each day, the treatment plant at Saidabad supplies 22.5 million litres of treated water to the capital's north-south pipeline that runs from Postogola Bridge to Farm Gate, and to the east-west pipeline which supplies water to the vast area from Goran through Old Dhaka to Dhanmondi. On the other hand, the Chandnighat plant supplies 3.9 million litres of treated water mainly in the localities under Lalbagh Police Station and Kotwali Police Station.
The intake point of the Saidabad plant is located at Sharulia, Demra and 500 metres upstream from the intake point, Balu River falls into Shitakkhya River. This means water from both Balu River and Shitalakhya River is used for treating water at the Saidabad plant. But because of ongoing water pollution both water sources are unfit to treat water through the conventional treatment plant, especially during the dry season. And the intake point of the Chandnighat plant is located near the Central Jail, and uses pitch black coloured water from the virtually dead Buriganga River.
Ammonia concentration in the Saidabad Water Treatment Plant, treated water has been found to be ten times higher than the standard set by the World Health Organisation (WHO) for dry seasons between January and April. Studies by Bangladesh University of Engineering and Technology (Buet), Design Planning and Management Consultants Limited (DPM), the Institute of Water Management (IWM), and Aqua, a water resources related private consulting firm, found concentration of diluted ammonia in SWTP treated water reaching up to 5.7 milligram (mg) per litre compared to the WHO 0.5 mg per litre safety limit set.
Dhaka Wasa supplies water after treating such contaminated river water at its two plants.
The high concentration of ammonia in the supplied water as well as excessive use of chlorine to treat highly polluted river water in both treatment plants during the dry season, makes the water sticky. High concentration of ammonia in supplied water is the result of the excessive disposal of domestic wastes, which fall into these rivers through several canals such as Begunbari Canal, Narai Canal, DND Canals and several other open drains.
According to a 'Study on Alternative Location of the Intake of Saidabad Water Treatment Plant', commissioned by Wasa in May 2006, everyday 3,500 cubic metres of wastewater containing waste load of 1,850 kilogram (kg) with a high level of biochemical oxygen demand (BOD) or the propensity to absorb oxygen from water containing organic waste, gets drained into the low lying lands of eastern Dhaka, which subsequently end up in the Balu river via Begunbari and Norai canals.
The physical and chemical analysis of Balu River water conducted at Bangladesh University of Engineering and Technology (Buet) in 2003, revealed that the total suspended solids (TSS) in the samples were 16 times higher than the level allowed by international standards while the BOD was 11 times higher than the standards, meaning the effluents may cause serious ecological and environmental damage by polluting the water of Balu River and the canals.
The dumped effluents deplete the oxygen level in the water bodies to a point when no living creature may survive in that water, reveals the report.
"And during the dry season the river carries only domestic wates and industrial effluents that highly pollutes the Shitalakkhya River", says Professor M Mujibur Rahman of BUET, under whose guidance the report was prepared.
On the other hand, the DND canal and the other open drains continue to dump high concentration of domestic waste into the Shitalakkya River, resulting in high levels of ammonia and algae concentration in the river water. The scenario of disposal of domestic waste in the water of Buginga is even more nauseating.
Industries just opposite to the intake point of Saidabad Water Treatment Plant at Sharulia
make difficult to treat water.
More alarming is that most of the industrial zones at Tejgaon Industrial Area and Hazaribagh Tannery and many other industries located on the banks of Balu River, Shitalakkhya River and Buriganga River do not use Effluent Treatment Plant (ETP). Which is why industrial wastes containing toxic heavy metals such as chromium, lead, cadmium, and magnesium mix into these rivers.
But only chlorine, lime and aluminium sulphate are used at both the conventional treatment plants to treat highly contaminated water of Balu, Shitalakhya and Buriganga for supplying to vast areas of Dhaka, says high officials of Dhaka Wasa. Several studies on the treatment plants recommend that the facilities at both SWTP and CWTP are inadequate for treating dangerously high concentration of ammonia, algae and industrial wastes such as chromium, lead and cadmium, which may cause serious kidney, liver, lung, stomach diseases and even cancer, among consumers.
Besides, the existence of high ammonia and algae contamination, there is every possibility of existing toxic heavy metals in supplied water, despite claims by Wasa that they test the water before supplying it.
Investigations says that usually only a few parameters such as Ph, Turbidity, Free Chlorine, Conductivity, TDS, Dissolved Oxygen, Faecal Coliform and Ammonia are tested in the treated water. But Wasa does not test any parameters of heavy metals that are harmful to health, such as chromium, lead, cadmium, and mercury in the treated water, though effluents from tanneries and other industries randomly carry such toxic metals into water sources of the treatment plants.
Though prohibited locals regularly bathe at the intake canal of Saidabad Water Treatment Plant.
A high level Wasa official, preferring anonymity, also says that none of the treatment plants can neutralise ammonia and harmful heavy metals, as they are not equipped to treat extremely polluted water. The official says provisions for treating exceptional parameters were not put in place in SWTP and CWTP because the rivers were not as polluted during the first phase of the plant's installation in the early 1990s.
Another high official of Wasa, on condition of anonymity, tells The Star Magazine, "Only highly sophisticated treatment plants, like the ones usually installed in atomic energy plants, can treat heavy metals in water."
Health experts warn that such a high level of ammonia, heavy metals, and industrial wastes in drinking water, and the high level of chlorine used to treat that water during dry seasons, put consumers at serious health risks including chances of getting kidney, liver, lung, and stomach diseases.
"Many health problems such as kidney complications, jaundice, gastro-intestinal complications and liver cirrhosis can be caused by higher concentration of ammonia in drinking water," says Professor ABM Faroque, a teacher of the department of pharmaceutical technology at Dhaka University.
Toilets at the canal bank pollute water, which is one of the major causes of getting sticky water in the supply pipeline of Dhaka Wasa.
But, Wasa engineers, citing WHO guidelines, deny that high concentration of ammonia in drinking water poses any threat to the users' health. Wasa however, runs daily tests of ammonia concentration in the water treated in SWTP.
A Wasa high official claims, "High concentration of ammonia makes the water malodorous, making it unacceptable to consumers. It doesn't pose any health risk," adding, "High concentration of ammonia is one of the major reasons for getting malodorous water in many areas of the city during dry seasons."
Professor ABM Faroque, however says, "WHO develops its guidelines in a gradual manner, and doesn't consider unusual cases like Bangladesh, where the source of water for treatment is totally contaminated by human and industrial wastes.”
Engineers of Dhaka Wasa also say treating water collected from the Balu river is very difficult and costly for Saidabad Water Treatment Plant, especially during the dry season, because the plant has to use extra chlorine to treat the extremely polluted water. The treated water also smells of chlorine due to the necessary heavy use of the chemical. SWTP engineers says they have to nearly double the volume of chlorine used in the plant to 60 kilograms per hour to treat contaminated water during the dry season.
Professor Faroque adds that high volumes of chlorine, lime, and aluminium sulphate used in the treatment plants to treat contaminated water from sources like the Buriganga, Balu and Shitalakkhya rivers, also pose serious health risks.
"A report by a journal of the Human Medicine Association reveals that high concentration of chlorine in water has a 94 percent chance of badly affecting corneas of humans. Moreover, it causes chlorine induced diarrhoea", he adds.
When Wasa Managing Director (MD) M Raihanul Abedin was contacted admitting a few problems such as bad smell in water he claimed that water supplied by Wasa is not a health hazardous. However, he expresses limitations in supplying water that is totaly free of contamination.
“It's not our failure that we cannot supply quality water during the dry season from the treatment plants that cover about 40 percent areas of Dhaka City. Unless, the water pollution is controlled we won't be able to do that either. Through several channels we've been trying to control ongoing water pollution, however, we have failed”, says the frustrated MD. He adds that disposal of industrial effluents into rivers must stop immediately, otherwise the water treatment plants might become useless.
Sources have confirmed that the Environment Cell of Wasa in 2003 detected many industrial plants as the main polluters of the river water. No action has yet been taken against them, though in April 2007 the Ministry of Industries, and the Ministry of Environment and Forest jointly told representatives of business communities that unless they install effluent treatment plants (ETP) in their factories before October 31 of the same year, supply of electricity, gas and water would be disconnected.
"However, no such action has yet been taken against the violators of government rules, although most of the industrial plants in Tajaribagh and Tejgaon Industrial Area are operating without having any ETP. And those which have installed ETPs, do not run any to save production costs", says, a high official of Wasa.
Wasa sources confirm that Danish International Development Agency (Danida) is providing technical support for setting up a pre-treatment plant for controlling the concentration of ammonia in pre-treated water at SWTP, but the project will not be very effective unless the disposal of the huge volume of domestic wastes through the canals into river water is stopped.
Wasa is planning to control the domestic waste disposal into Balu River through several projects such as Begunbari-Hatirjhil Beautification Project and installing a waste treatment plant at Dasherkandi. If these projects were implemented properly, disposal of domestic wastes would be controlled through Narai canal. But, Wasa has no plan to control such disposal in DND canal, nor has it any plan to protect CWTP. It, moreover, does not admit the deplorable state its sewage system is in at the eastern part of Dhaka city. For a better solution, says the Wasa MD, Wasa needs to use better surface water sources from Meghna River and Padma River for treatment.
(R) thedailystar.net 2009