Dhaka Water Supply and Sewerage Authority continues using chlorine, a dangerous chemical for human consumption, as the High Court is yet the hear a rule issued on January 11, 2010 asking for explanation of legality of the use of chlorine at the Saidabad Water Treatment Plant Phase II.
WASA uses liquid chlorine gas, alum sulphate and cold lime for treating the water of Sitalakkhya for disinfection and purification to make it drinkable at the Saidabad Water Treatment Plant phase-I. The process is known as ‘break point chlorination’.
The founding chairman of Bangabandhu Sheikh Mujib Medical University, Syed Akram Hussain, told New Age that chlorine could cause different kinds of cancer.
‘According to the World Health Organisation, chlorine in drinking water could cause bladder cancer,’ he said, adding ‘Chlorine can
also cause rectal and gastrointestinal cancer.’
Taking bath with chlorinated water can cause skin diseases that also may turn into cancer, Akram said.
Dhaka WASA invited tenders for the Saidabad Water Treatment Plant phase-II project in 2008 and also carried out a feasibility study.
The feasibility study said, ‘Break point chlorination is by far the cheapest means using marginal capital and operational costs which is also tricky and normally not used for drinking water treatment with these levels of ammonia and organic carbon.’
‘We tested one sample of raw water for break point chlorination by adding 70 milligram chlorine per litre, but found no reduction in the ammonia concentration which indicates that the organic carbon in the water constitutes a very high chlorine demand, and this will almost certainly form tri-halomethanes and other haloforms which are carcinogenic and highly organoleptic,’ it added.
The study also said, ‘The process will remove ammonia, make the water more biologically stable and enable more efficient removal of algae in the treatment process, but it may not remove the organoleptic substances creating the smell and taste,’ and added, ‘Chlorine will react immediately with any sulphides with a demand of close to 9mg chlorine gas per mg sulphides.’
According to sources in the department of environment, a meeting was held at the department on August 5, 2009 in respect of the Saidabad Water Treatment Plant phase-II.
As the river water contains organic substances like — fulvic acid, humic acid and algae, the pre-chlorination would cause formation of trihalomethanes which was dangerous to health, the meeting observed.
The High Court on January 11, 2010, after hearing a writ petition, issued a rule asking the government and the Dhaka WASA to explain why the acceptance of the tender for using chlorine at the Saidabad Water Treatment Plant phase ll as responsive would not be declared illegal.
The cabinet committee on public purchase, however, on January 14, 2010, approved the tender for using chlorine at the plant, although the lowest bidder had offered for using sodium permanganate for purification of the river water.
The rule is yet to be heard, the petitioner’s counsel Nurul Islam last week said.
Meanwhile, the construction work of the project is going on.
The project manager, Martial Dautrey, told New Age on June 22 that chlorine was being used at the plant’s phase-I and it would be used accordingly in phase-II, as chlorination was easier and common process for water treatment.
He, however, said that people in United States and European countries would not drink water with smell of chlorine.
Dhaka WASA managing director Taqsem A Khan, told New Age, ‘We use chlorine for purifying the river water as chlorination is the cheapest method.’
Asked about the risks of using chlorine, he said that they were following the method as it was being used in different countries for long.
He also mentioned that they were using chlorine at the doses approved by the World Health Organisation.
A source at the plant said, ‘As the water of Sitalakkhya contains harmful chemicals, including human wastes, dyes and other chemicals, it requires mixing of more quantity of chemicals for purification.’
As the Sitalakkhya water is more polluted in dry season, three to four times more chemicals are used for the treatment of water in dry season than in rainy season, he said adding that 100 kilograms of liquid chlorine gas per hour, 12 tons of alum sulphate and four tons of cold lime are used daily at the treatment plant between January and April.
Taqsem also said, ‘As the Sitalakkhya water is more polluted in dry season, additional chlorine and alum sulphate are used that causes smell in the treated water, but it is safe for drinking.’
Taber’s Cyclopedic Medical Dictionary defines chlorination as the addition of chlorine or one of its derivatives to water to kill microorganisms.
It says, ‘Some studies have suggested an association (but not a causal link) between the chlorination of drinking water and the incidence of cancer and birth defects.’
The Journal of Orthomolecular Medicine, a renowned medical journal, in its Volume 15, 2nd Quarter, 2000, said, ‘Long-term risks of consuming chlorinated water include excessive free radical formation, which accelerates aging, increases vulnerability to genetic mutation and cancer development, hinders cholesterol metabolism, and promotes hardening of arteries.’
‘Chlorinated water appears to increase the risk of gastrointestinal cancer over a person’s lifetime by 50 to 100 per cent and is associated each year in America with about 4,200 cases of bladder cancer and 6,500 cases of rectal cancer,’ it said, adding, ‘Chlorine is estimated to account for nine per cent of bladder cancer cases and 18 per cent of rectal cancers.’
According to US Council of Environmental Quality, ‘Cancer risk among people drinking chlorinated water is 93 per cent higher than among those whose water does not contain chlorine.’
-With New Age input
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