Desalination plant cleared at last
Chennai Water Desalination Limited has finally received its environmental clearance for the 100 million litres per day plant to be set up in North Chennai. The environmental clearance was obtained after recommendations were made by The Central Marine Fisheries Institute to ensure that there would be no adverse impact to the environment and coast near the plant. The plant is scheduled to start production of 15 million litres per day by April next year, in time for Tamil New Years Day. Full production capacity of 100 million litres will be achieved by July 07 according to the report in The Hindu. Will this finally mean we will see the end of water supply problems in the city? And more importantly, the end of the water tanker menace to city roads? Only time will tell.
One can always hope. Desalination plants have worked wonders for the people living in the middle east. It’s a pity that even with such a long coastline, our country citizens do not have basic amenities. More than fifty years after independence we are still talking of providing drinking water to all.
And how much power will it take to run this plant?
Will we have to sit in the dark to drink our water?
Surely it would have been so much better to improve the harvesting and storage of rainwater than to invest in this neat but expensive and power-hungry technology?
Will this finally mean we will see the end of water supply problems in the city? And more importantly, the end of the water tanker menace to city roads?
No, and no. 100 MLPD is less than 15 liters per person per day (LPPPD) for Chennai’s population. You need to provide at least 100 LPPPD in total (*). Note that this excludes industries, all of which have their own water treatment units anyway. Assume the existing monsoon-based infrastructure (Red Hills / Sholavaram / Poondi / Chembarambakkam) can safely supply 35 LPPPD year-round, you need at least THREE MORE desalination plants, of the same capacity as the one being built. Even if you assume the existing infrastructure can supply 50 LPPPD (year-round), the single desalination plant won’t make too much of a difference by itself. Until those extra plants are built, you’ll still see tankers plying the streets.
(Yes, I am a chemical engineer, and I have worked on sea water desalination through multistage flash distillation and through reverse osmosis).
(Also, Musafir: desalination has been much more economically viable for the Middle East due to cheap energy. It’s not as viable for India due to energy cost. Having a long coastline does not influence availability of potable water in any way, so please don’t confuse the issue).
(*) Reference: FALKENMARK, M. and WIDSTRAND, C. Population and water resources: A delicate balance. Population Bulletin 47(3): 1-36. Nov. 1992.
GLEICK, P. Basic water requirements for human activities: Meeting basic needs. International Water 21(2): 83-92. 1996.
Thanks Che. That certainly puts it in perspective! Clearly it will have to be a ,ulti-pronged aproach to ensure sufficient drinking water for Chennai’s current and growing needs.
Che, Thanx.
dear people,
My name is Sujith and I am doing an MBA in UK. I am looking at the sustainable-economic factors of the chennai desalination plant in terms of energy. Is there any journal or documents i can refer for information about the energy requirements of the project. Are any alternative sources of energy advised for the plant ?
You are welcome to reply directly to my email address too.
thanks
Sujith