The Hindu Business Line : Sewage water recycling a money-spinner

Wastewater is no more a waste but a money-spinner. Industries are looking at the effluent from homes as a cheap source of water. "The more wastewater homes churn out, the more we will take,'' they say.

Look at these official statistics: The Chennai Metropolitan Water Supply and Sewerage Board (Metro Water) earned over Rs 5 crore selling 23 million litres of sewage a day to industries in North Chennai, which recycled it for their own use. There is money down the drain and it is flowing back.

Multiple advantages

There are multiple advantages in this arrangement, say industry representatives. Metro Water gets rid of its waste and earns money, industry gets a cheap source of water and the industry is no longer competing for freshwater which can be spared to meet domestic requirements.

So why cannot the wastewater be made available to industries at a lower cost, they ask?

Cost and benefit

The scheme has taken off in a big way at Manali, the industrial suburb to the north of Chennai, where a large refinery, fertiliser units and chemical industries are located. These are water-guzzling industries that need several thousand gallons of water a day.

Mr J. Paneerselvam, Secretary, Manali Industries' Association, says the industries in Manali need about 45 million litres of water a day. It can be a problem in Chennai, a water-starved city, if industries have to compete for water with the residents.

For instance in 1993-94, many units in the area had to shutdown because the authorities cut water supply to the industries to ensure supplies to residents. Last year, during the drought water charges skyrocketed, he says.

Piped water supply costs about Rs 60 a kilolitre - twice that of what it cost in the 1980s - but only about half of Manali's requirement was available so they depended on water tankers, which meant that prices went up to Rs 80-100 a kilolitre.

But Chennai Petroleum Corporation Ltd (CPCL) and Madras Fertilizers Ltd have opted for a cheaper solution - sewage water. Of course, they have to put in recycling systems before it could be used in their units.

CPCL's options

According to Mr S. Chandrasekaran, General Manager, CPCL, it needs about 6.5-7 million gallons water a day. The options it has are raw water from piped supply about 4-4.3 million gallons a day, sewage water about 2.5 million gallons a day, which after treatment gives about 1.9 million gallons and the balance is recycled water from CPCL's own effluent.

More economical

Sewage water is by far the more economical option because CPCL buys it at about Rs 8.30 a kilolitre and after treatment to get clean water the cost works out to about Rs 30-35 — about half that of piped supply.

CPCL is moving towards expanding its water treatment facilities and is doubling its sewage water treatment facilities. By 2007-end, the company will be self sufficient in its water requirement.

According to CPCL officials, saving water by recycling makes more freshwater available to the public, Metro Water's revenue is enhanced, and sewage, a pollutant is taken out of the system. Metro Water should encourage this scheme by reducing sewage water costs.

Mr Sukumar N. Oommen, Chairman and Managing Director, Madras Fertilizers Ltd, says it is the State Government that first encouraged the industries to set up sewage treatment facilities. Apart from getting a cheap source of water, the industries are helping Metro Water to dispose of the sewage; therefore, the sewage water cost could be reduced for mutual benefit, he adds.

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