Utilization of textile sludge and public health risk assessment in Bangladesh

Textile wastewater is one of the major water pollution concerns in the manufacturing countries. However, the sludge from these wastewater treatment plants is often discarded to the environment and therefore is exposed to flood with rain causing the soil and water contamination. Therefore, there is a growing need to look for various applications of sludge handling for sustainable development. Typical textile sludge was found to have very high (∼80%) moisture content, however the dry sludge had a decent heating value (> 17 MJ kg−1). Different textile sludge/clay mixtures (0.5–5.25% dry sludge) were used to make bricks, which were evaluated in terms of their compressive strengths and the leaching behavior. The textile sludge incorporated clay fired bricks showed up to 77% more compressive strength compared to average standard bricks. The leaching test of clay-fired cubes exhibited very low water absorption (0.8–1.3%), which is desirable for various applications. From the cytotoxicity assessment of textile industrial sludge, lethal Concentration 50% was found to be at 262 μM concentration of sludge solution, based on Cr level. This value is significantly higher than the leachate concentration and thus indicates the potential of sludge as a building material without the possibility of heavy metal contamination to surroundings.