CHENNAI : Fly ash from thermal power plants, once a major air pollutant, is now being made into bricks or added as a mixture to cement for building construction, laying of roads and landfills.

"Fly ash is not a waste, but an asset," was the theme of the Tiruvallur District Fly Ash Implementation Committee's second meeting on Tuesday at the Ennore Thermal Power Station and the North Chennai Thermal Power Station .

Chaired by the Tiruvallur District Collector Ranvir Prasad, members from the PWD, Tamil Nadu Pollution Control Board (TNPCB), National Thermal Power Corporation (NTPC) participated in the discussions.

V. Vivekanandan, Executive Engineer, Ash Handling System, ETPS, said ash generation in the three units at ETPS was 1,900 tonnes per day; this would go up when units I and IV begin to generate power shortly, taking ash generation up to 3,000 tonnes. The ash was collected manually till December 2006, but since then the fly ash is being collected in jumbo bags. From April 14, the collection has been through the pressurised dense fly ash collection system (PDFACS) and lifted through bulkers. The ash from two units is being collected round the clock by PDFACS and jumbo bags. The remaining fly ash and bottom ash is mixed with seawater as slurry and pumped into ash dykes and kept as wet ash.

The Ash Tech company has speeded up the PDFACS Work and trial pumping of fly ash from a unit, Mr. Vivekanandan said.

In 2005-06, utilisation of fly ash was 26.17 per cent, exceeding the target of 20 per cent. There will be 100 per cent utilisation by the end of 2007 with the help of PDFACS and use of wet ash for road and land filling works. Allotment orders were issued to two companies for dry fly ash in 2005-06. Wet ash allotment has been issued to five companies. The Collector said the committee members and officials of the thermal stations were working towards the target of 100 per cent ash utilisation. There was also a call for working with the Highways Department for using fly ash in the proposed construction of the Tiruvottriyur-Ponneri-Panchetti road.

S. Arounassalame, Chief Engineer, NCTPS, said that their present allotment of fly ash for 2006-07 was 9.57 metric tonne against the target of 7.62 lakh metric tonnes. The action plan target for 2006-07 was 53 per cent. PDFACS and manual arrangements have been erected in all six rows of the three units.

V. Santhana Krishnan, Superintending Engineer, Civil Design said that there was also a proposal to use fly ash for agricultural purposes. M. Hari Babu, Chief Engineer, ETPS and S. Jegatheesan, Superintending Engineer, Civil, ETPS, spoke.

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