Background In recent years, ambitious city wastewater purifying programmes have been implemented across Europe. This has led to a considerable increase in the sludge generated by sewage treatment plants, which is either deposited in landfills or incinerated. Increasingly, it is also processed to produce fertiliser. However, sludge generally contains heavy metals and organic substances, and the environmental and health impact of its use as fertiliser has not yet been fully investigated. Objectives The Eco_Ceramics project's main objective was to reduce the environmental impact generated by the sludge coming from the Waste Water Treatment Plants (WWTP), through a new sludge management concept tahta introduces a method that re-uses sludge as raw material for the structural ceramics industry (for manufacturing rough bricks). During the process, the organic substances in the sludge were eliminated through burning, while the heavy metals, if they were present in the sludge, were safely contained. Furthermore, energy is saved during the production process since sludge is used as a combustible. The project also aimed to address the issue of transporting the sludge from wastewater treatment plants to industrial sites. Results Technically the Eco-Ceramics project has demonstrated that the WWTP sludge could be viably used in the mixture to produce ceramic bricks. The chemical composition, the energy properties of the sludge and the mineral and technological performance of the clay were analysed in a laboratory. The conclusions were that: WWTP sludge can be used to produce ceramics by being integrated into the current mixture without negative effects on the characteristics of the ceramic products; The percentage of sludge that can be added is between 1 and 10%. The studies concluded that the optimum quantity is 1% of sludge in the current mixture used in the industrial process; however the maximum viable percentage is 2,5%, which allows a margin in case of variations in the sludge and ceramic production. The most suitable temperature for baking the clay is 1 050ºC. A semi-industrial phase followed aimed at the production of actual bricks as a preliminary step before industrial demonstration. Tests were conducted and they demonstrated that 1% of mud waste used to create the bricks was the most suitable percentage and that the introduction of the WWTP sludge should not have any effect on the technological properties of the bricks, or on other phases of the production process. There was a small decrease in brick quality but this was considered to be negligible and had no impact on the quality of the final product. The results suggest that this technology could be transferred to the industrial sector for large scale production, taking into account the maximum percentage of waste from WWTP which is recommended for use in the manufacturing process. Ceramicas Peño (the industrial partner in the project) produced 79 000 bricks using dry waste mixed at 1% with the clay material normally used. The manufacturing process took place in the same industrial conditions as the conventional mixes/materials and the results were found to be satisfactory. Technically, there were no differences between these bricks and the ones usually manufactured by the company. No adaptations were needed regarding the packaging, logistics and other activities related to the manufacturing and transport of the rough brick manufactured with waste. Secondly, in parallel, analytical results on the dry waste demonstrated that it is not toxic, so no special measures/permits would be necessary to transport it from the WWTP to the ceramic industries. The transport of dry waste could thus be carried without any problems, as is usual in the case of traditional clay material. Thirdly, different possibilities for the management and thermal treatment of the waste from the WWTP were studied. The design of the prototype selected was based on a tank mixer with external heat transfer, which was chosen for its simplicity and versatility. The energy used to heat the water was supplied by two 50 KW biomass boilers. The humidity achieved by the final sludge was not higher than 20%. To conclude, the Eco-Ceramics project demonstrated that WWTP sludge could be used to produce ceramic bricks without generating negative consequences for the product. This would have positive environmental implications, including: a reduction in the disposal of the WWTP sludge and a reduction in carbon dioxide emissions in the ceramic industries as, according to the project’s results, the use of sludge could lead to a net energy saving for the ceramic industry of around 6% of its consumption. A meeting also took place with the technical manager of another LIFE funded project “LOTECOTEC” (LIFE 06 ENV/D/000458) who was very interested in the results achieved by the Eco-Ceramics project. The only disadvantage is that the use of the sludge from WWTP, without stabilization, produces, in the opinion of some participants, an unpleasant smell during the normal drying process. This was seen as the only aspect which could limit its acceptance by the industry. Further information on the project can be found in the project's layman report and After-LIFE Communication Plan (see "Read more" section).