Waste pre-treatment companies allow the cement industry to substitute natural non renewable raw materials and fuels such as coal. The use of waste derived fuel in European cement kilns saves fossil fuels. This represents 5 million tonnes of coal per year. In addition to energy recovery, there is a corresponding greenhouse gas saving, mainly CO2 emissions not released into the atmosphere. This waste may contain mineral components that will be recovered in the kiln as substituted raw material.

The history of co-processing in cement kilns started in the mid seventies when the petroleum crisis drastically increased the cost of fuel oil and when, in different countries, new regulations were issued on waste management.

For some waste such as used oils, tyres or solvents co-processing in cement kilns was an immediate solution and logical answer to the situation from both environmental and economical points of view.

Then, in order to increase the energy and material savings from waste, more and more sophisticated pre-treatment processes have been developed, first to produce liquid substitution fuel and  solid substitution fuel and raw materials.