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The cement sector has become a recognised leading player in the recovery of material and heat from numerous sources of waste. The use of alternative fuels, rigorously selected for their compatibility with the cement-making process, is as justified by the rise in the cost of traditional fuels as it is by the need to eliminate non-hazardous or special industrial waste and make a positive impact on the environment.
Waste management is a major issue for industries that need to find technically and ecologically acceptable solutions as part of an overall sustainable management policy. Since the 1980s, Ciments Calcia has participated in this collective effort through investments at all its production sites. Alternative fuels now account for around one quarter of its energy requirements. In 2004, the Saintes community of districts in Charentes Maritimes (France) invited bids for tender for the recovery of the combustible fraction of its household waste, comprised of wood, paper, separated and shredded board and plastics, and non-hazardous industrial waste. After separating out metals and minerals and removing the fermentable matter, which is landfilled, the remainder, around 20%, is ground and then screened before delivery to the Bussac plant. The Bussac project devoted a team of six people for two years to the design, operation and validation of performance tests for the use of this waste as an alternative fuel in the cement-manufacturing process. After a conclusive testing period, in compliance with the Administrative Authorities, and having provided continuous information about the project’s evolution to the CLIS (Local Information and Supervisory Commission) and the CCSE (Environmental Consultation and Supervisory Commission) since 2004, Ciments Calcia decided to invest € 2 million in a new facility for the recovery of this waste material as an alternative source of energy.
The new facility, operational since August 2006, has four sheltered delivery points that merge into two collectors. The material is weighted and then fed either into the main burner or into the precalciner. The combustion of this material in place of fossil fuels is an ideal method of recovering optimal heating power from the waste and so reducing greenhouse gas emissions associated with cement manufacture. It is expected that use of this category of fuel will gradually rise from the current 6,000 t/yr to 20,000 t/yr. This replacement could account for 15% of the total fuel requirement by 2008-2009.In addition to effectively eliminating the waste stream, this process makes a significant reduction to greenhouse gas emissions from waste, as household waste comprises around 30% biomass.
With operating temperatures of around 1,500°C, the cement-manufacturing process results in the complete destruction of organic compounds, and so can be a solution for the elimination of industrial sludge with a low energy value. To help reduce the environmental impact of this type of industrial waste, the Beaucaire site has installed a unit designed to receive, store, weigh, transfer and inject dewatered treatment sludge into the riser duct of the kiln.This project, which cost around u 800,000, was developed in partnership with SCORI, a company specialised in the recovery and pre-treatment of industrial waste. With a potential of 6,000 t/yr, the site is able to eliminate 1 to 2 t/hr. The CCSE (Environmental Consultation and Supervisory Commission) has met in Beaucaire every year since 1996, and provides the ideal forum for discussing and sharing points of view with local stakeholders. This investment programme was presented, along with other matters, at the meeting at the end of 2005, giving the participants the opportunity to understand its importance and the benefits for the region.
Use of waste material must comply with very precise regulations and inspection procedures up- and down-stream in the recovery process. Fully aware of its responsibilities, Ciments Calcia is continually strengthening its inspection procedures. The company implements very stringent internal procedures for the delivery of the raw material, its combustion and resultant emissions in order to guarantee the safety of its employees and the communities neighbouring its cement plants, and in order to meet the strict quality standards for its cement products.
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