Industry urged to recycle waste water

Even as the Tamil Nadu government is taking up two desalination projects at Minjur and Nemili in public-private partnership mode, the fact remains that Chennai is yet to develop a fully effective water and waste water management industry.

The Chennai Metropolitan Water Supply and Sewerage Board (Metro Water) is directing its attentions to this phenomenon, and addressing the need to actively involve the industry in waste water recycling.

At TN Aqua 2007, a conference on emerging trends in water management, Metro Water managing director Shiv Das Meena noted that 450 MLD (million litres per day) of secondary effluent treatment capacity is available in Chennai, but only 41 MLD is being treated currently.

Meena stressed the need to find innovative ways to meet future water requirements. With urbanisation, population growth, use of modern agriculture practices and mismanagement, Chennai's water needs are increasing.

"Chennai is expected to need around 2,260 MLD by 2026. Although, sources for about 1,950 MLD are identified, the solution lies in conservation and recycling to generate 300 MLD by 2026," he said.

Metro Water supplies 570 MLD for domestic use and 35 MLD for industries. It also supplies another 35 MLD to adjacent urban centres.

However, the city has enough water to meet its current requirements, thanks to satisfactory water levels at its main surface reservoirs of Red Hills, Cholavaram, Poondi, and adequate supply from Veeranam, Chembarambakkam Lake and the Telugu Ganga Project.

Consequently, the government has been able to reduce ground water usage from 100-125 MLD a few years ago to 30 MLD.

Meena called on industry to tap the huge potential in recycling waste water for industrial use and save costs. "The cost of recycling would work out much cheaper than the cost of procuring water from reverse osmosis and desalination units," Meena said.

He appealed to the industry not to treat waste water as waste but as "used water" that can be effectively reused, resulting in cost savings. He urged the industry to become zero discharge units, especially as the necessary technologies are becoming increasingly affordable.

Metro Water is already supplying 36 MLD of secondary treated water to companies such as Chennai Petroleum Corporation Ltd and Madras Fertilizers Ltd, and about 5 MLD to GMR's Vasavi power project.

Amit Sen Gupta, co-convenor, Energy, Environment & Occupational Health Panel, CII "� Tamil Nadu, said the cost of water treatment technologies have fallen sharply down the years. If the cost of a technology was Rs 100 in 1985, it has been brought down to Rs 11 in 2006, thanks to technological advances and wider adoption.

He urged industry to look out for opportunities afforded by cost reduction of technologies and felt that the government should consider setting up reverse osmosis plants in North Chennai and a few more in South Chennai.

Nandini Rangaswamy, chairperson, Taskforce on Water, CII-Tamil Nadu, said that integrated water management practices involving water conservation, recycling and reuse in industries offer both economic and environmental advantages.

Reuse of treated waste water for industrial and other purposes closes the loop on the water use cycle, thus preventing wastage of water. Subsequently, the pressure on existing freshwater resources will also reduce, she said.

According to several estimates, industrial water use in India today stands at about 40 billion cubic metres, or nearly 8 per cent of total freshwater abstraction in the country.

With globalisation and increasing economic activity, industrial water consumption is estimated to double over the next two decades, resulting in increased stress not only on water availability for industries but also for population and agriculture.