Cement, Energy and Environment

other wastes in cement plants (Central Pollution Control Board, 2017). There are also examples of providing waste management solutions to other industries through utilizing waste streams such as municipal solid waste, biomass, mixed industrial waste, resource derived fuel to power its cement plants. For instance, Ambuja Cement's initiative under Geocycle brand has reported to have facilitated reduction of carbon emissions of around 10.3 million tonnes of CO (FICCI, Accenture 2 Strategy, 2018). Challenges in implementing circularity A sustainable economy without circular flows is hard to imagine. To name a few, models such as cradle-to- cradle, biomimicry and industrial ecology heavily emphasize recycling and reuse activities. Although circular economy is the next step to be sustainable, this road to sustainability is fraught with considerable challenges. The life cycle of cement begins with raw material extraction such as limestone and ends at concrete production. Increasing resource efficiency by minimizing waste at each step of its life cycle offers not only significant opportunities but also notable challenges to the cement industry. While opportunities include a reduction in both capital and operational expenditure by using alternative raw materials, and strengthening of cement quality through co-processing of waste, challenges entail planning and creating an efficient and effective industrial symbiosis among different industries. For instance, the cost of transporting alternative raw materials may be higher than using traditional raw materials, thus making the symbiosis unviable and reducing resource efficiency. Another concern in linking different industries is creating a complex interdependent system. Such a complicated network implies that a change in one industry can lead to a domino effect in the remaining industries, which may result in a collapse of the entire web. With the government pushing for renewable energy, growth of thermal power plants may become weaker in future. Fly ash from thermal power plants currently used as a raw material in blended cement could therefore require substitution. Apart from this, sustainable ventures may not seem attractive unless either the industry is pressurized by external forces such as the government or the venture is an obvious cost-effective measure. For instance, cement manufacturing companies may not recycle concrete in construction and demolition waste unless a government mandate for the same is passed. Moreover, dumping of such waste may be a cheaper option than its recycling (Singhi, 2017). The principles of circular economy pose significant opportunities for minimizing waste and contributing to a healthy ecological and social balance. However, research in this regard is usually carried out in a conducive ecosystem which is then generalized for the global industry. Such research interventions when applied in a particular geography may fail to show the intended results. For instance, 30-40% of kiln heat in the European cement industry is derived from burning of waste materials, whereas despite its huge potential, this value has only reached 4% in India (Singhi, 2017). These hindrances preclude a key player from participating in the circular economy, and thereby limit the potential benefits arising from such transition. Incorporating circularity in the cement industry The five major components in manufacturing cement described above provide major opportunities to the cement 9