Evaluating Technical Properties of Fired Clay Brick Production with Mosaic Sludge: A Comprehensive Study on Heavy Metal Leachability for Sustainable Environmental and Economic Benefits

Abstract

Mosaic sludge, generated from mosaic industrial activities such as cutting, polishing, and grinding, is often disposed of in landfills or discharged into drainage systems without adequate treatment. This study aims to reuse mosaic sludge from the mosaic industry by incorporating it into fired clay bricks. This approach offers an alternative disposal method, improves brick quality, and minimizes heavy metal leachability, contributing to environmental and economic sustainability. X-Ray Fluorescence (XRF) was conducted to determine the heavy metal concentration from two types of mosaic sludge bodymill mosaic sludge (BS) and polishing mosaic sludge (PS). The result indicates that the highest element concentration in mosaic sludge (BS and PS) shows that barium is the highest with 3253 ppm and 3260 ppm. Meanwhile, the lowest element concentration obtained in BS and PS is cesium with 14 ppm and 17 ppm. SPLP and TCLP also conducted in this study and the result show that, even though the element such as ferum (Fe) and cadmium (Cd) was not detected in XRF but in SPLP and TCLP, it shows that these two elements exist in clay, BS and PS with low concentration. In order to evaluate the compressive strength conducted by incorporating with different proportions 0%, 1%, 5%, 10%, 20% and 30% of BS and PS into fired clay brick. The result shows that compressive strength BS brick was stronger than PS brick. The maximum sludge percentage used in BS brick is 5% with value of compressive strength is 28.10 MPa. Meanwhile, PS brick had the higher value of compressive strength at 30% sludge percentage with the value 23.46 MPa. Static Leachate Test (SLT) was performed to evaluate heavy metal leachability from bricks containing different proportions of BS and PS sludge. In the SLT results, Fe exhibits the highest concentration of heavy metals at various proportions of BS and PS: 2.11 mg/L and 2.27 mg/L at 1%, 1.77 mg/L and 1.88 mg/L at 5%, 2.34 mg/L and 3.29 mg/L at 20%, and 2.79 mg/L and 3.64 mg/L at 30% respectively, among other elements. On the other hand, elements including Cr, Ni, Cu, As, Cd, and Pb demonstrated lower concentrations ranging from 0.00 mg/L - 1.0 mg/L. The result for control brick, BS brick and PS brick shows the same pattern. However, overall results show that the concentration still under limit set by USEPA.