What have rice husk, hazelnut shells, paper sludge or cow dung got to do with cement manufacturing?

The answer lies in the fact that Madras Cement Ltd, the flagship company of Ramco Group, is using such waste materials as alternative fuels and saving over Rs 8 crore annually.

Or that UltraTech's Gujarat Cement Works is utilising tyre chips, rubber dust and other such material, resulting in reduction of about 30,000 tonnes of carbon emission a year. And that Lafarge's Arasmeta plant is substituting almost 10 per cent of the coal used in its kilns with rice husk to increase energy savings and reduce carbon emission.

Indeed, cement majors are increasingly burrowing through newer industrial, municipal and agricultural wastes to utilise these as alternative fuels to fire their kilns, not only to save costs but also contribute to India's efforts to snip carbon intensity by 25 per cent of 2005 level by 2020.

This is part of a world-wide trend in the cement sector, with the Japanese cement industry utilising over 450 kg of waste per tonne of cement manufactured and European plants achieving a thermal substitution rate of over 40 per cent.

“If the Indian cement industry can increase thermal substitution to just five per cent, GHG (greenhouse gas) emissions could reduce by over 17 lakh tonnes of carbon annually,” says Mr G. Jayaraman, Executive President of Birla Corporation Ltd.

India produces over six million tonnes of hazardous waste and about 50 million tonnes of non-hazardous and municipal wastes, apart from a large quantity of agro-waste. With cement making capacity set to increase from about 320 million tonnes this fiscal to 550 mt by the end of the next Plan Period, industry planners feel that cement makers should further sharpen focus on alternative fuels.

Cement majors are taking new initiatives in this direction. Madras Cement's Alathiyur plant, for example, has demonstrated that burning of pet coke and alternative fuels such as coffee husk and cashew nut shells could result in a saving of Rs 8 crore annually — its average pet coke consumed is about 82,000 tonnes and alternative fuel about 9,000 tonnes.

Similarly, India Cements Ltd's Dalavoi plant has shown that consumption of just 30 tonnes of LSHS sludge, which has a heat value of over 9000 kCal/kg, can result in savings of about Rs 3 lakh annually.

Dalmia Cement has identified ‘red mud' as an effective substitute for high-cost bauxite (used as additive to manufacture clinker) — this is an industrial waste from Malco's aluminium plant.

ACC's Madukkarai unit launched Project Zero Fuel Cost in early 2010, when thermal substitution rate was 0.9 per cent. It increased the rate to 3.41 per cent by use of wastes from textile units, rejected shampoos and face powder and plastic.

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