A concrete green initiative

Waste from the pharmaceutical industry has always been a critical problem, and its elimination a controversial subject.

Generated as both hazardous and solid waste, techniques used over the years for its management include incineration, secure land filling, immobilisation through encapsulation or inertisation. But all these have proved to be far from ideal. These methods waste a resource that can be used as an alternative energy to save fossil fuels.

Using pharma waste along with other waste in cement kilns, or co-processing as it is called, during cement manufacturing, has proved to be a good fit. And since the 1970s, Europe, the US, Japan, Canada and Australia have successfully co-processed different kinds of waste as alternative fuels and raw materials (AFR) in cement kilns.

The cement industry in India, the second largest in the world, too warmed up to the idea some years ago and currently uses almost 75 million tonnes of waste as replacement for raw materials and fuels in factories across the country. This includes some units that use pharma waste and have proved the enormous potential it throws up for a larger tie-up between the two sectors.

Last fortnight, case studies brought out at the Cement Manufacturers Association’s fourth conference on “Alternate Fuel and Raw Materials in Cement Industry – Conserve 2019” in New Delhi, flagged some of these projects. Pertinent among them were examples of pharma waste being used for AFR.

In one of the case studies, author ASC Bose of India Cements Ltd described the effort of its Malkapur Works, 120 km from Hyderabad. As Hyderabad is a growing hub for the pharma industry, the possibility of using pharma waste as AFR was explored. Since December 2016, the company has managed to co-process 11,793 MT of pharma waste at its unit. It used pharma’s high calorific value waste such as organic residue, liquid and solid organic spent solvents, spent carbon whose use as alternate fuel has been proven and permitted after the Central Pollution Control Board (CPCB) ran trial runs.

To utilise the waste, India Cements installed a dedicated AFR Solvent firing feeding system. This is a 30kl capacity organic solvent tank where the liquid waste is unloaded and pumped through a main burner at the rotary kiln outlet to ensure complete destruction of AFR.

Simultaneously, the solid waste from the pharma industry is stored in a 500 MT capacity shed. Later it is mixed to uniform mixture and is conveyed through closed belt conveyor system for feeding the calciner. Bose points out that the calorific value of AFR received from pharma waste varies between 2500 kcal per kg to 3500 kcal per kg and has resulted in reduced coal consumption. Another case study is by M Laxmaiah and R V Krishna Kumar of My Home Industries Private Ltd. (MHIPL). At its Mellacheruvu Cement Works in Telangana it initiated co-processing of pharma liquid waste as a thermal substitution. In 2012, with the support of FL Smith, Denmark, it installed an AFL handling system which includes unloading, storage and pumping of pharma liquid waste in cement kilns. Over the years the thermal substitution rate has scaled up to 2.58 per cent, with the company targeting 5 per cent.

These two examples go to show the potential of pharma waste as fuel, something that has been emphasised by the CPCB when it set the guidelines for co-processing in 2010. It called the utilisation of hazardous wastes for co-processing a win–win situation.

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