In order to reduce the consumption of non-renewable fossil fuels and to give an effective and safe response to society when it comes to handling waste, the cement sector has made a determined wager in favour of the diversification of its energy sources.
Cement plants offer a very good opportunity in this sense, as the characteristics of their manufacturing process allow them to recover the energy from several waste streams under optimal technical and environmental conditions. By rendering this service to society, the activity of the cement industry is making a major contribution to the environment.
The process of sinterization of clinker at high temperatures requires a large amount of fuel and gives the possibility of recovering the energy from certain types of organic waste by using them instead of traditional fossil fuels (petroleum coke, coal, diesel, ...).
The replacement of fossil fuels by waste implies a safe, environmentally-friendly way of treating it while making the most of the energy and minerals it contains without generating additional impacts on the environment and reducing greenhouse gas emissions.
Guarantees of use
In addition, energy recovery from waste takes place with the following assurances:
Alternative fuels come from authorized waste handlers and are only accepted after a check of their composition and verification of their suitability for use in the cement plant.
During energy recovery, the parameters ensuring proper combustion and the emissions of the process are all monitored to confirm that they comply with the conditions established by the competent authorities. These conditions are detailed in Directive 2000/76/EE and in Royal Decree 256/2003, applicable to all industries performing combustion of waste and much stricter than those applied to normal operations.
The recovery of energy from waste in cement kilns has become more popular in Spain in recent years for the following reasons:
Greater awareness among Spain's Regional Goverments, the Public Administrations with the greatest responsability for these matters, with regard to the importance of sustainable waste managements. In 2009, Ministry for Environmental Affairs started the works to transpose to the Spanish legislation the Directive 2008/98/CE on the wastes, that force the Member States to realise some type of valuation of the wastes and promote the use of recoverred materials in order to diminish the spill and to preserve the natural resources. This necessity has been shown in different working sessions with the participation of the interested parts.
The publication of new scientific reports on the guarantees of recovery in cement plants, as the URS study on “Emissions and its possible effects on the health in cement plants surroundings”. After analyzing the emissions in four representative cement plants and their possible transmission throughout the food chain, the study concludes that these emissions do not suppose a risk for the population and the workers of the surroundings, and the use of alternative fuels do not increase factors of risk.
Some remarkable scientific studies have been realised as the study of the Alicante University based on the use of sewage sludge and fuels from urban solid wastes in Alicante cement plant, confirming that the use of these alternative fuels do not suppouse and additional impact because of they do not alter the emissions.
Support of the Environment Ministry and Ministry of Industry, which acknowledge, in the latest National CO2 Allocation Plan, the use of biomass waste and alternative fuels as the main tool necessary to reduce emissions in this sector.
Close collaboration with employees, reinforced with the implementation of the Cement and the Environment Foundation, known in Spanish as the CEMA Foundation. This Foundation was set up following the signing, in 2004, of the Agreement on the recovery of energy from waste in the cement industry, between Oficemen, the association representing cement manufacturers in Spain, and the sectorial trade union sections, FECOMA-CC.OO. and MCA-UGT.
Greater information for citizens in the towns where this activity takes place, thanks to a policy of transparency and communication by companies and a commitment by local authorities towards the environmental benefits for their region. Moreover, in 2010 the website www.recuperaresiduosencementeras.org shows the whole information regarding the use of waste materials in the cement industry.
In 2010 the Supreme Court Justice of Comunidad Valenciana dictated a fovourable sentence about co-incineration of wastes in Buñol plant, after the resource presented by some groups. This sentece is added to the 2009 senteces (TSJ Castilla-La Mancha and TSJ of Cantabria) that ratify the legal use of alternative fuels in cement plants.
Following the example of other European countries and the principles of waste management, the Spanish cement sector is increasing the use of alternative fuels. It used about 792,000 tonnes of waste as fuel in 2011, i.e. 22.4% of the thermal consumption of the clinker kilns.
Waste recovery, a top priority in the European Union
Of the 250 clinker plants operating in the European Union, more than 160 burn waste as their fuel. The replacement of fossil fuels by waste, although increasing every year, is still unusual in Spain if we compare it with other nearby countries, especially Holland, Switzerland, France, Austria, Belgium or Germany, where waste management systems have spent decades reducing waste impact and taking advantage of cement kilns as waste processing facilities. Spain’s statistics when it comes to replacing fossil fuels by waste are far below the average for European countries with advanced environmental awareness, but the cement sector is aiming to change that trend.