Work

Comparative Effects of Sewage Sludge and Sewage Sludge–Biomass Briquette Ash on Phase Evolution, Microstructure and Performance of Fired Clay Bricks

Year: 2026

Type: article

Abstract: This study investigates the potential use of sewage sludge (SS) and sewage sludge ash obtained from the combustion of sewage sludge–wood-chip briquettes (BSSA) as additives in fired clay bricks. The novelty of this study lies in comparing these two waste-derived additives within the same clay matrix. Clay mixtures containing 5–20 wt.% SS or BSSA were prepared and fired at 1000 °C. The raw materials and fired products were characterized using chemical and thermal analyses, X-ray diffraction (XRD), and scanning electron microscopy with energy-dispersive spectroscopy (SEM–EDS). Compared with the control specimens, SS incorporation reduced bulk density by 10–35% and compressive strength by 32.5–62.8%, while BSSA reduced these properties by 8–18% and 29.6–58.8%, respectively. Water absorption increased with both additives. Microstructural observations indicated increased pore formation, particularly in SS-containing specimens, consistent with the burnout of organic constituents during firing. The results suggest that incorporation levels of 5–10 wt.% offer a more favorable balance of properties than 20 wt.%. The use of BSSA may support cascade waste utilization by combining energy recovery with subsequent ash reuse.

Source: Buildings

DOI: 10.3390/buildings16214311

Authors: Olga Kizinievič, Viktor Kizinievič, Osman Gencel, Violeta Voišnienė

Institutions: Vilnius Gediminas Technical University, Bartin University

Language: English

Topic: Recycling and utilization of industrial and municipal waste in materials production

Subfield: Building and Construction

Field: Engineering

Domain: Physical Sciences

SDGs: Responsible consumption and production, Sustainable cities and communities

Open Access status: gold

Estimated APC paid: $3,137