Incorporation of paper sludge in clay brick formulation : ten years of industrial experience

The large amounts of sewage sludge (11 million tonnes in Europe in 2005) produced in paper manufacturing plants require the introduction of recycling and/or alternative recovery solutions to minimize the amounts of generated waste, such as its use in soil remediation or in the cement industry. A feasible alternative to valorize that waste is the use of paper sludge as raw material in the production of structural ceramic or clay bricks. Previous studies tried to incorporate sewage sludge from different sources into ceramic matrices, unfortunately with little success in the final result for most types of sludge. However, those experiments carried out using as additive sludge from the paper industry succeeded in producing amaterial suitable for the red ceramic industry. In this paper, binary mixtures of clay and paper sludge under different formulations were produced and their physico-chemical properties were studied. Increasing the paper sludge content in the clay mixture provides the material with improved properties regarding its thermal and acoustic insulation, but in turn it decreases its mechanical strength. However, this fragility of the material is compensated by an increased ductility. Regarding metal leaching, the studied ceramics have no environmental restrictions as far as their use as building material is concerned, as the obtained results were virtually identical to those for the blank samples (100% clay). Results showed that the presence of dichloromethane (373.2 µg m-3) and propanone (61.2 µg m-3) in the samples with added sludge was relatively relevant with respect to concentrations in samples made of 100% clay. All monocyclic aromatics detected showed a concentration level far below their odor threshold. In general, thus, it can be concluded that volatile organic compound (VOC) emissions during firing of the new ceramic material do not involve any particular problem. Finally, the experience obtained after more than 10 years of industrial production of this new mixed ceramic product was also analyzed. This analysis allowed confirmation that clay brick productionwith incorporation of paper sludge waste is a feasible solution froma technical point of view. As a key outcome, this fact has helped the reduction in a large proportion the amount of sludge produced by the Spanish paper industry ending up in landfills.Peer ReviewedPostprint (author’s final draft

Custom formulation of red ceramics with clay, sewage sludge and forest waste

The large quantities of sewage sludge that are currently generated require new alternatives for its recycling and final destination, beyond already known methods in the agriculture and cement industry. The use of this sludge as raw material for the production of structural ceramics, such as clay bricks, may become an interesting alternative, both from an industrial and environmental point of view. Several investigations have addressed this issue by formulating binary mixtures of sludge with clay. However, the incorporation of forest waste into the binary mixture described in this paper allows a high amount of sewage sludge to be assimilated into an extrudable mix and represents a better choice for the valorization of this hazardous waste. In this study the physicochemical properties of several formulations of ternary mixtures were analyzed. A ternary pseudo diagram was obtained relating the physicochemical properties of the ceramic product to the fraction of the raw materials. The optimal ternary mixture of 10% sludge, 10% forest waste and 80% clay, yielded a ceramic material with compression strength of 96 kp/cm2. It also met the technological limit of 8 bar to give and extrudable material. The mixture would be suitable for building ceramics, with low thermal conductivity (0.31 W/m·K) and high porosity (59.4%). The environmental aspects of the production of these ceramics were investigated by leaching and outgassing tests.Peer ReviewedPostprint (published version

Custom formulation of red ceramics with clay, sewage sludge and forest waste

The large quantities of sewage sludge that are currently generated require new alternatives for its recycling and final destination, beyond already known methods in the agriculture and cement industry. The use of this sludge as raw material for the production of structural ceramics, such as clay bricks, may become an interesting alternative, both from an industrial and environmental point of view. Several investigations have addressed this issue by formulating binary mixtures of sludge with clay. However, the incorporation of forest waste into the binary mixture described in this paper allows a high amount of sewage sludge to be assimilated into an extrudable mix and represents a better choice for the valorization of this hazardous waste. In this study the physicochemical properties of several formulations of ternary mixtures were analyzed. A ternary pseudo diagram was obtained relating the physicochemical properties of the ceramic product to the fraction of the raw materials. The optimal ternary mixture of 10% sludge, 10% forest waste and 80% clay, yielded a ceramic material with compression strength of 96 kp/cm2. It also met the technological limit of 8 bar to give and extrudable material. The mixture would be suitable for building ceramics, with low thermal conductivity (0.31 W/m·K) and high porosity (59.4%). The environmental aspects of the production of these ceramics were investigated by leaching and outgassing tests.Peer Reviewe

Aplicaciones de la termografía infraroja y la espectrorradiometría en el estudio del deterioro del patrimonio nacional

Son conocidos los problemas que la acción de los agentes atmosféricos causa a nuestro patrimonio monumental. Sin duda, el aumento de la contaminación atmosférica contribuye a aumentar las causas naturales del deterioro de las piedras que constituyen nuestro legado histórico. Lamentablemente, el conocimiento científico parcial de las causas que producen el denominado "mal de piedra", ha conllevado a restauraciones inapropiadas que, en no pocas ocasiones, lejos de solucionar el problema, han incrementado el proceso de deterioro o degradación. La necesidad de encontrar métodos de diagnóstico rápidos y eficientes, especialmente los denominados como técnicas de análisis no destructivos, ha dado lugar a la aplicación de la Termografía Infrarroja (TIR) y la Espectrorradiometría (ER) como herramientas de apoyo al estudio del deterioro de las piedras monumentales y cuyos primeros resultados presentamos en este trabajo.Peer Reviewe

Using solid wastes as raw materials in clay bricks

The large quantities of sewage sludge that are currently generated require new alternatives for its recycling and final destination, beyond already known methods in the agriculture and cement industry. The use of this sludge as raw material for the production of structural ceramics, such as clay bricks, may become an interesting alternative, both from an industrial and environmental point of view. This chapter is focused on the use of solid wastes, such as for example sewage sludge or forest residues, to serve as additive raw materials for the production of clay bricks. It is based on our experience with the Ecobrick material and our subsequent research on producing some raw materials from WWTP sludge suitable for the ceramic industry. The chapter shows some formulations of raw materials in ceramic mixtures, their physical properties and to analyze their environmental characteristics. The final purpose is to illustrate the possibility of designing tailor-made ceramics that fulfill custom-physical properties, which are appropriate for particular construction use

Incorporation of paper sludge in clay brick formulation : ten years of industrial experience

The large amounts of sewage sludge (11 million tonnes in Europe in 2005) produced in paper manufacturing plants require the introduction of recycling and/or alternative recovery solutions to minimize the amounts of generated waste, such as its use in soil remediation or in the cement industry. A feasible alternative to valorize that waste is the use of paper sludge as raw material in the production of structural ceramic or clay bricks. Previous studies tried to incorporate sewage sludge from different sources into ceramic matrices, unfortunately with little success in the final result for most types of sludge. However, those experiments carried out using as additive sludge from the paper industry succeeded in producing amaterial suitable for the red ceramic industry. In this paper, binary mixtures of clay and paper sludge under different formulations were produced and their physico-chemical properties were studied. Increasing the paper sludge content in the clay mixture provides the material with improved properties regarding its thermal and acoustic insulation, but in turn it decreases its mechanical strength. However, this fragility of the material is compensated by an increased ductility. Regarding metal leaching, the studied ceramics have no environmental restrictions as far as their use as building material is concerned, as the obtained results were virtually identical to those for the blank samples (100% clay). Results showed that the presence of dichloromethane (373.2 µg m-3) and propanone (61.2 µg m-3) in the samples with added sludge was relatively relevant with respect to concentrations in samples made of 100% clay. All monocyclic aromatics detected showed a concentration level far below their odor threshold. In general, thus, it can be concluded that volatile organic compound (VOC) emissions during firing of the new ceramic material do not involve any particular problem. Finally, the experience obtained after more than 10 years of industrial production of this new mixed ceramic product was also analyzed. This analysis allowed confirmation that clay brick productionwith incorporation of paper sludge waste is a feasible solution froma technical point of view. As a key outcome, this fact has helped the reduction in a large proportion the amount of sludge produced by the Spanish paper industry ending up in landfills.Peer Reviewe

Using solid wastes as raw materials in clay bricks

The large quantities of sewage sludge that are currently generated require new alternatives for its recycling and final destination, beyond already known methods in the agriculture and cement industry. The use of this sludge as raw material for the production of structural ceramics, such as clay bricks, may become an interesting alternative, both from an industrial and environmental point of view. This chapter is focused on the use of solid wastes, such as for example sewage sludge or forest residues, to serve as additive raw materials for the production of clay bricks. It is based on our experience with the Ecobrick material and our subsequent research on producing some raw materials from WWTP sludge suitable for the ceramic industry. The chapter shows some formulations of raw materials in ceramic mixtures, their physical properties and to analyze their environmental characteristics. The final purpose is to illustrate the possibility of designing tailor-made ceramics that fulfill custom-physical properties, which are appropriate for particular construction use.Postprint (published version

Ecobrick: a new ceramic material for solar buildings

Ceramic materials technology has been known for a very long time. In the construction field, ceramics are considered ecological or natural materials with acceptable structural and thermal characteristics. Besides, these characteristics can be improved by changing the composition of the raw material. In this respect the Ecobrick(R) Project aims at optimizing some of those properties and achieving thereby important environmental benefits. In our study, we used sludges from urban wastewater treatment plants together with other wastes and clays, to produce a new ceramic material suitable for construction. When using Ecobrick(R), energy consumption can be reduced up to 49% and the Solar Saving Fraction will increase up to 14% compared both to conventional ceramics.Peer Reviewe

Using solid wastes as raw materials in clay bricks

The large quantities of sewage sludge that are currently generated require new alternatives for its recycling and final destination, beyond already known methods in the agriculture and cement industry. The use of this sludge as raw material for the production of structural ceramics, such as clay bricks, may become an interesting alternative, both from an industrial and environmental point of view. This chapter is focused on the use of solid wastes, such as for example sewage sludge or forest residues, to serve as additive raw materials for the production of clay bricks. It is based on our experience with the Ecobrick material and our subsequent research on producing some raw materials from WWTP sludge suitable for the ceramic industry. The chapter shows some formulations of raw materials in ceramic mixtures, their physical properties and to analyze their environmental characteristics. The final purpose is to illustrate the possibility of designing tailor-made ceramics that fulfill custom-physical properties, which are appropriate for particular construction use

Ecobrick: a new ceramic material for solar buildings

Ceramic materials technology has been known for a very long time. In the construction field, ceramics are considered ecological or natural materials with acceptable structural and thermal characteristics. Besides, these characteristics can be improved by changing the composition of the raw material. In this respect the Ecobrick(R) Project aims at optimizing some of those properties and achieving thereby important environmental benefits. In our study, we used sludges from urban wastewater treatment plants together with other wastes and clays, to produce a new ceramic material suitable for construction. When using Ecobrick(R), energy consumption can be reduced up to 49% and the Solar Saving Fraction will increase up to 14% compared both to conventional ceramics.Peer Reviewe