Reuse of textile mill ETP sludge in environmental friendly bricks - effect of gamma radiation

Textile mill is the largest industry in Bangladesh facing problem of sludge disposal. In this study, gamma irradiated (15 kGy) textile mill ETP sludge was used to make environmental friendly eco-bricks. According to the percentage (%) of sludge and soil content in brick samples, bricks were graded as E (50% sludge+50% soil), F (25% sludge + 75% soil), G (25% sludge+ 70% soil + 5% sand), X (10% sludge+ 90% soil) and Y (100% soil). A 100% soil content normal commercial brick (N) was also compared with these bricks. All the bricks were fired at 450 °C for 24 h. Physico-chemical analysis of both sludge and soil were studied. Parameters such as density, weight loss (%), firing shrinkage (%), bending strength (BS), bending modulus (BM), impact strength (IS), water uptake (%) and electrical resistivity were investigated. Density, weight loss, firing shrinkage, electrical resistivity reduces as sludge content (%) in bricks increases whereas BS, BM, IS and water uptake (%) increases. The change of density of all bricks has been experienced during the ageing tests in water, acid, alkali and salt. Morphological analysis of the brick samples were done by Inverted Microscope. Finally, change of water pH has been studied during the ageing period.