The paper “Recovering wastes from the paper industry: Development of ceramic materials” outlines research into the recovery of two forms of waste from the paper industry: sludge from the purification of wastewater and residue from cleaning the pulp.
The continuous generation of industrial waste and the environmental problems it causes makes it necessary to find alternative methods for treating waste, the paper says. The researchers found the sludge residue can be used in ceramic materials such as bricks, an addition that saves raw materials and energy.
The waste-based bricks have lower mechanical strength compared to traditional bricks. However, the researchers hope to improve the strength of the bricks in further testing.
Researchers began by collecting cellulose waste, specifically sludge from wastewater treatment, from a paper recycling factory and mixed it with clay used in construction.
The mixture was then shaped and put through an extrusion machine to form one long piece of material, which was then sliced into individual bricks and ultimately fired in a kiln, according to SINC, a state-wide public agency in Spain that specializes in information on science, technology and innovation.
The addition of waste allows the final product to present a low thermal conductivity, so it acts as a good insulator, said Carmen Martinez, a researcher at the University of Jaén, according to SINC. The bricks’ organic content can help reduce fuel consumption and the firing time required during the production process.
A report released by Frost & Sullivan last month said the industrial sludge treatment chemicals market in Western Europe, valued at €635.2 million ($1.02 billion) in 2011, will reach €808.8 million ($1.3 billion) in 2018, growth driven by intensifying environmental awareness and stricter regulations related to discharge processes and disposal.