Building materials strengthened with sewage sludge
S. Himmelstein | March 09, 2021Materials researchers in Russia have devised a method for strengthening structural ceramics while simultaneously realizing environmental benefits. The addition of wastewater treatment plant sludge to clay batches yields a durable ceramic as a potential construction material and reduces the volume of sludge requiring treatment and disposal.
Researchers from South Ural State University and Peter the Great St. Petersburg Polytechnic University Samples of the ceramics obtained by adding sewage sludge. Source: Danil Rakhimov/South Ural State Universitydetermined that freeze-thaw technology was effective in producing dewatered sludge with optimal properties for inclusion in synthesized ceramics. A two-factor experiment varied the amount of sludge in the clay and the firing temperature. The introduction of the treated sludge additive served to reduce the density of the ceramics by 20% and lowers the firing temperature by 50° C without loss of sintering.
Inclusion of the sludge additive produced by the freeze-thaw process reduces the sensitivity of the clay to drying, leading to a reduced drying time and defect rate. A 20% addition of the processed sludge also increases the compressive strength of ceramic bricks from 7.0 MPa to 10.2 MPa. The process can be applied to wastewater treatment plant sludge containing aluminum, obtained by treating water of medium turbidity and medium color.
The research is published in Materials.