28 May,2011 06:45 AM IST | | Rinkita Gurav
Instead of chlorine, the BMC is mulling the option of the oxygen variant to purify water at its treatment plants; it's a tricky decision as both have their pros and cons
While it's layer in the stratosphere has been riddled with giant holes, the BMC is contemplating the use ozone to purify the water that reaches your home, much like most European countries.
However, the pros of chlorine it stays longer in water and is cheaper holding them back.
A BMC official on the condition of anonymity said, "Engineers are studying the use of ozone to disinfect water. Although it is not feasible for the city, we are still trying to find ways of doing so."
"Ozone is much better than chlorine as a disinfectant but it is costlier.
Also, it vanishes from the water within a couple of hours. In Mumbai, the water takes that much time to reach the consumer from the treatment plant, so that makes it a negative factor," he said.
While chlorine remains in the water for 8-9 hours after addition, ozone lasts 2-3 hours.
Municipal Commissioner Subodh Kumar is of the opinion that chlorine is more hazardous. It is combustible if it comes in contact of some other element. "Ozone is a better disinfectant.
It kills harmful bacteria from the water. We are still studying its use as it can be a better choice."
BMC's Standing Committee Chairperson Rahul Shewale said, "After studies, we found that once an ozone generator is set up at the treatment plant, using ozone can be cost effective. We are still awaiting the results of studies on it."
The BMC uses 4,300 tonnes of chlorine per year for disinfecting water at both its treatment plants. Theu00a0 BMC spends Rs 130 crore per year buying chlorine.
Expertspeak
A senior IIT-Bombay professor said, "In India, ozone cannot be feasible only because of the distribution networks.
Although there are reports from some European countries that ozone is u00a0better than chlorine, it is u00a0not used in the US. There has to be a reason for that. It should be monitored before use."
He continued, "Ozone has the properties of oxidising all the elements in water but its validity is less which makes chlorine a better option in Mumbai.
Also, if chlorine gives rise to hazardous situations, only then should something else be adopted. Currently, that is not the case. It seems to be like a marketing gimmick.
u00a0
It is also expensive. In Europe, electricity is cheaper, unlike India. So an ozone generator would work out to beu00a0 expensive."
Number Game
4,300
Quantity (tonnes) of chlorine the BMC uses for disinfecting water every year
8-9
The number of hours chlorine remains in the water
Rs 7,100
The cost of chlorine per tonne
